<!DOCTYPE html><html><head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
  </head>
  <body>
    <div class="moz-cite-prefix">hmm.. it is my concern for the same
      instance. but I got it now. Your patch is good. <br>
    </div>
    <div class="moz-cite-prefix">Thanks,</div>
    <div class="moz-cite-prefix">David<br>
    </div>
    <div class="moz-cite-prefix">On 2025-08-14 14:06, Lazar, Lijo wrote:<br>
    </div>
    <blockquote type="cite" cite="mid:DS0PR12MB7804E1DB7C7882D3F0EA7EED9735A@DS0PR12MB7804.namprd12.prod.outlook.com">
      
      <p style="font-family:Calibri;font-size:10pt;color:#0000FF;margin:5pt;font-style:normal;font-weight:normal;text-decoration:none;" align="Left">
        [AMD Official Use Only - AMD Internal Distribution Only]<br>
      </p>
      <br>
      <div>
        <div dir="auto" style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt;">
          I didn't fully understand the question. </div>
        <div dir="auto" style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt;">
          <br>
        </div>
        <div dir="auto" style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt;">
          For the same instance, begin_thread will set the power state
          only after cancelling any idle worker for the instance. If
          idle worker is already under progress, then it needs to
          complete as that's a cancel_sync (it's the existing logic).</div>
        <div dir="auto" style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt;">
          <br>
        </div>
        <div dir="auto" style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt;">
          Basically, by the time begin_thread sets the PG state, no idle
          worker for the same vcn instance would be active. If it's
          about context switch to another vcn instance's begin_thread, I
          think that won't be a problem.</div>
        <div id="ms-outlook-mobile-body-separator-line" dir="auto"><br>
        </div>
        <div id="ms-outlook-mobile-signature" style="font-family: Aptos, Aptos_MSFontService, -apple-system, Roboto, Arial, Helvetica, sans-serif; font-size: 12pt;" dir="auto">
          <div dir="auto">Thanks,</div>
          <div dir="auto">Lijo</div>
        </div>
        <hr style="display:inline-block;width:98%" tabindex="-1">
        <div id="divRplyFwdMsg" dir="ltr"><font face="Calibri, sans-serif" style="font-size:11pt" color="#000000"><b>From:</b> Wu, David
            <a class="moz-txt-link-rfc2396E" href="mailto:David.Wu3@amd.com"><David.Wu3@amd.com></a><br>
            <b>Sent:</b> Thursday, August 14, 2025 11:14:26 PM<br>
            <b>To:</b> Lazar, Lijo <a class="moz-txt-link-rfc2396E" href="mailto:Lijo.Lazar@amd.com"><Lijo.Lazar@amd.com></a>;
            Sundararaju, Sathishkumar
            <a class="moz-txt-link-rfc2396E" href="mailto:Sathishkumar.Sundararaju@amd.com"><Sathishkumar.Sundararaju@amd.com></a>; Alex Deucher
            <a class="moz-txt-link-rfc2396E" href="mailto:alexdeucher@gmail.com"><alexdeucher@gmail.com></a><br>
            <b>Cc:</b> Wu, David <a class="moz-txt-link-rfc2396E" href="mailto:David.Wu3@amd.com"><David.Wu3@amd.com></a>; Deucher,
            Alexander <a class="moz-txt-link-rfc2396E" href="mailto:Alexander.Deucher@amd.com"><Alexander.Deucher@amd.com></a>;
            <a class="moz-txt-link-abbreviated" href="mailto:amd-gfx@lists.freedesktop.org">amd-gfx@lists.freedesktop.org</a>
            <a class="moz-txt-link-rfc2396E" href="mailto:amd-gfx@lists.freedesktop.org"><amd-gfx@lists.freedesktop.org></a><br>
            <b>Subject:</b> Re: [PATCH] drm/amdgpu/vcn: fix video
            profile race condition (v3)</font>
          <div> </div>
        </div>
        <div class="BodyFragment"><font size="2"><span style="font-size:11pt;">
              <div class="PlainText">amdgpu_vcn_idle_work_handler():<br>
                     if (!fences &&
                !atomic_read(&vcn_inst->total_submission_cnt)) {<br>
                ----------- could it be possible a context switch here
                to <br>
                amdgpu_vcn_ring_begin_use()?<br>
                  if it could then AMD_PG_STATE_GATE will be set by
                mistake.<br>
                <br>
                David<br>
                <br>
                On 2025-08-14 08:54, Lazar, Lijo wrote:<br>
                > [Public]<br>
                ><br>
                > The request profile can be moved outside the
                pg_lock in begin_use as in the attached patch. It needs 
                set power state -> set profile order.<br>
                ><br>
                > This is the premise -<br>
                ><br>
                > Let's say there are two threads, begin_use thread
                and idle_work threads. begin_use and idle_work will need
                the workprofile mutex to request a profile.<br>
                ><br>
                > Case 1) Idle thread gets the lock first.<br>
                >          a) Idle thread sees vinst power state as
                PG_UNGATE, no harm done. It exits without requesting
                power profile change. begin_use thread gets the lock
                next, it sees profile as active and continues.<br>
                >          b) Idle thread sees vinst power state as
                PG_GATE, it will make workprofile_active to false and
                exit. Now when begin_use thread gets the mutex next,
                it's guaranteed to see the workprofile_active as false,
                hence it will request the profile.<br>
                ><br>
                > Case 2) begin_use thread gets the lock first.<br>
                >          a) Workload profile is active, hence it
                doesn't do anything and exits. The change made by
                begin_use thread to vinst power state (state = on) will
                now be visible to idle thread which gets the lock next.
                It will do nothing and exit.<br>
                >          b) Workload profile is inactive, hence it
                requests a profile change. Again, the change made by
                begin_use thread to vinst power state will now be
                visible to idle thread which gets the lock next. It will
                do nothing and exit.<br>
                ><br>
                > Thanks,<br>
                > Lijo<br>
                ><br>
                > -----Original Message-----<br>
                > From: Sundararaju, Sathishkumar
                <a class="moz-txt-link-rfc2396E" href="mailto:Sathishkumar.Sundararaju@amd.com"><Sathishkumar.Sundararaju@amd.com></a><br>
                > Sent: Thursday, August 14, 2025 6:18 PM<br>
                > To: Lazar, Lijo <a class="moz-txt-link-rfc2396E" href="mailto:Lijo.Lazar@amd.com"><Lijo.Lazar@amd.com></a>; Alex
                Deucher <a class="moz-txt-link-rfc2396E" href="mailto:alexdeucher@gmail.com"><alexdeucher@gmail.com></a><br>
                > Cc: Wu, David <a class="moz-txt-link-rfc2396E" href="mailto:David.Wu3@amd.com"><David.Wu3@amd.com></a>; Deucher,
                Alexander <a class="moz-txt-link-rfc2396E" href="mailto:Alexander.Deucher@amd.com"><Alexander.Deucher@amd.com></a>;
                <a class="moz-txt-link-abbreviated" href="mailto:amd-gfx@lists.freedesktop.org">amd-gfx@lists.freedesktop.org</a><br>
                > Subject: Re: [PATCH] drm/amdgpu/vcn: fix video
                profile race condition (v3)<br>
                ><br>
                ><br>
                > On 8/14/2025 5:33 PM, Lazar, Lijo wrote:<br>
                >> [Public]<br>
                >><br>
                >> There is no need for nested lock. It only needs
                to follow the order<br>
                >>           set instance power_state<br>
                >>           set profile (this takes a global lock
                and hence instance power state will be visible to
                whichever thread that gets the work profile lock).<br>
                >><br>
                >> You are seeing nested lock just because I added
                the code just after power state setting.<br>
                > Pasting your code from the file for ref :<br>
                ><br>
                > @@ -464,32 +509,14 @@ void
                amdgpu_vcn_ring_begin_use(struct amdgpu_ring<br>
                > *ring)<br>
                ><br>
                > -pg_lock:<br>
                ><br>
                >        mutex_lock(&vcn_inst->vcn_pg_lock);<br>
                >        vcn_inst->set_pg_state(vcn_inst,
                AMD_PG_STATE_UNGATE);<br>
                ><br>
                > +   amdgpu_vcn_get_profile(adev);<br>
                ><br>
                > vcn_pg_lock isn't  released here yet right ? And
                in-case you intend to only order the locks, then still
                there is an un-necessary OFF followed by ON, but yes
                that is acceptable,<br>
                ><br>
                > May be you want to move that vcn_pg_lock after
                amdgpu_vcn_get_profile to protect concurrent dpg_state
                access in begin_use.<br>
                ><br>
                > The concern is, this patch access power_state that
                is protected by some other mutex lock hoping it reflects
                right values also when holding powerprofile_lock.<br>
                ><br>
                > Or<br>
                ><br>
                > Have shared a patch with global
                workload_profile_mutex that simplifies this handling,
                and renamed pg_lock -> dpg_lock  and used<br>
                ><br>
                > that only for dpg_state changes per instance.<br>
                ><br>
                > Regards,<br>
                ><br>
                > Sathish<br>
                ><br>
                >> Thanks,<br>
                >> Lijo<br>
                >><br>
                >> -----Original Message-----<br>
                >> From: Sundararaju, Sathishkumar
                <a class="moz-txt-link-rfc2396E" href="mailto:Sathishkumar.Sundararaju@amd.com"><Sathishkumar.Sundararaju@amd.com></a><br>
                >> Sent: Thursday, August 14, 2025 5:23 PM<br>
                >> To: Lazar, Lijo <a class="moz-txt-link-rfc2396E" href="mailto:Lijo.Lazar@amd.com"><Lijo.Lazar@amd.com></a>;
                Alex Deucher<br>
                >> <a class="moz-txt-link-rfc2396E" href="mailto:alexdeucher@gmail.com"><alexdeucher@gmail.com></a><br>
                >> Cc: Wu, David <a class="moz-txt-link-rfc2396E" href="mailto:David.Wu3@amd.com"><David.Wu3@amd.com></a>;
                Deucher, Alexander<br>
                >> <a class="moz-txt-link-rfc2396E" href="mailto:Alexander.Deucher@amd.com"><Alexander.Deucher@amd.com></a>;
                <a class="moz-txt-link-abbreviated" href="mailto:amd-gfx@lists.freedesktop.org">amd-gfx@lists.freedesktop.org</a><br>
                >> Subject: Re: [PATCH] drm/amdgpu/vcn: fix video
                profile race condition<br>
                >> (v3)<br>
                >><br>
                >><br>
                >> On 8/14/2025 3:16 PM, Lazar, Lijo wrote:<br>
                >>> [Public]<br>
                >>><br>
                >>> I see your point now. Attached should work,
                I guess. Is the concern more about having to take the
                lock for every begin?<br>
                >> This is closer,  but the thing is, IMO we
                shouldn't have to use 2 locks and go into nested
                locking, we can do with just one global lock.<br>
                >><br>
                >> Power_state of each instance, and global
                workload_profile_active are<br>
                >> inter-related, they need to be guarded
                together,<br>
                >><br>
                >> nested could work , but why nested if single
                lock is enough ? nested complicates it.<br>
                >><br>
                >> Regards,<br>
                >><br>
                >> Sathish<br>
                >><br>
                >>> Thanks,<br>
                >>> Lijo<br>
                >>><br>
                >>> -----Original Message-----<br>
                >>> From: amd-gfx
                <a class="moz-txt-link-rfc2396E" href="mailto:amd-gfx-bounces@lists.freedesktop.org"><amd-gfx-bounces@lists.freedesktop.org></a> On Behalf
                Of<br>
                >>> Lazar, Lijo<br>
                >>> Sent: Thursday, August 14, 2025 2:55 PM<br>
                >>> To: Sundararaju, Sathishkumar
                <a class="moz-txt-link-rfc2396E" href="mailto:Sathishkumar.Sundararaju@amd.com"><Sathishkumar.Sundararaju@amd.com></a>;<br>
                >>> Alex Deucher <a class="moz-txt-link-rfc2396E" href="mailto:alexdeucher@gmail.com"><alexdeucher@gmail.com></a><br>
                >>> Cc: Wu, David <a class="moz-txt-link-rfc2396E" href="mailto:David.Wu3@amd.com"><David.Wu3@amd.com></a>;
                Deucher, Alexander<br>
                >>> <a class="moz-txt-link-rfc2396E" href="mailto:Alexander.Deucher@amd.com"><Alexander.Deucher@amd.com></a>;
                <a class="moz-txt-link-abbreviated" href="mailto:amd-gfx@lists.freedesktop.org">amd-gfx@lists.freedesktop.org</a><br>
                >>> Subject: RE: [PATCH] drm/amdgpu/vcn: fix
                video profile race condition<br>
                >>> (v3)<br>
                >>><br>
                >>> [Public]<br>
                >>><br>
                >>> That is not required I think. The power
                profile is set by an instance *after* setting itself to
                power on. Also, it's switched back after changing its
                power state to off.  If idle worker is run by another
                instance, it won't be seeing the inst0 as power gated
                and won't change power profile.<br>
                >>><br>
                >>> Thanks,<br>
                >>> Lijo<br>
                >>> -----Original Message-----<br>
                >>> From: Sundararaju, Sathishkumar
                <a class="moz-txt-link-rfc2396E" href="mailto:Sathishkumar.Sundararaju@amd.com"><Sathishkumar.Sundararaju@amd.com></a><br>
                >>> Sent: Thursday, August 14, 2025 2:41 PM<br>
                >>> To: Lazar, Lijo <a class="moz-txt-link-rfc2396E" href="mailto:Lijo.Lazar@amd.com"><Lijo.Lazar@amd.com></a>;
                Alex Deucher<br>
                >>> <a class="moz-txt-link-rfc2396E" href="mailto:alexdeucher@gmail.com"><alexdeucher@gmail.com></a><br>
                >>> Cc: Wu, David <a class="moz-txt-link-rfc2396E" href="mailto:David.Wu3@amd.com"><David.Wu3@amd.com></a>;
                Deucher, Alexander<br>
                >>> <a class="moz-txt-link-rfc2396E" href="mailto:Alexander.Deucher@amd.com"><Alexander.Deucher@amd.com></a>;
                <a class="moz-txt-link-abbreviated" href="mailto:amd-gfx@lists.freedesktop.org">amd-gfx@lists.freedesktop.org</a><br>
                >>> Subject: Re: [PATCH] drm/amdgpu/vcn: fix
                video profile race condition<br>
                >>> (v3)<br>
                >>><br>
                >>> Hi Lijo,<br>
                >>><br>
                >>> On 8/14/2025 2:11 PM, Lazar, Lijo wrote:<br>
                >>>> [Public]<br>
                >>>><br>
                >>>> We already have a per instance power
                state that can be tracked. What about something like
                attached?<br>
                >>> This also has concurrent access of the
                power state ,<br>
                >>> vcn.inst[i].cur_state is not protected by
                workload_profile_mutex<br>
                >>><br>
                >>> every where, it can still change while you
                are holding workload_profile_mutex and checking it.<br>
                >>><br>
                >>> Regards,<br>
                >>><br>
                >>> Sathish<br>
                >>><br>
                >>>> Thanks,<br>
                >>>> Lijo<br>
                >>>> -----Original Message-----<br>
                >>>> From: amd-gfx
                <a class="moz-txt-link-rfc2396E" href="mailto:amd-gfx-bounces@lists.freedesktop.org"><amd-gfx-bounces@lists.freedesktop.org></a> On Behalf
                Of<br>
                >>>> Sundararaju, Sathishkumar<br>
                >>>> Sent: Thursday, August 14, 2025 4:43 AM<br>
                >>>> To: Alex Deucher
                <a class="moz-txt-link-rfc2396E" href="mailto:alexdeucher@gmail.com"><alexdeucher@gmail.com></a><br>
                >>>> Cc: Wu, David
                <a class="moz-txt-link-rfc2396E" href="mailto:David.Wu3@amd.com"><David.Wu3@amd.com></a>; Deucher, Alexander<br>
                >>>> <a class="moz-txt-link-rfc2396E" href="mailto:Alexander.Deucher@amd.com"><Alexander.Deucher@amd.com></a>;
                <a class="moz-txt-link-abbreviated" href="mailto:amd-gfx@lists.freedesktop.org">amd-gfx@lists.freedesktop.org</a><br>
                >>>> Subject: Re: [PATCH] drm/amdgpu/vcn:
                fix video profile race<br>
                >>>> condition<br>
                >>>> (v3)<br>
                >>>><br>
                >>>><br>
                >>>> On 8/14/2025 3:38 AM, Alex Deucher
                wrote:<br>
                >>>>> On Wed, Aug 13, 2025 at 5:1 PM
                Sundararaju, Sathishkumar<br>
                >>>>>
                <a class="moz-txt-link-rfc2396E" href="mailto:sathishkumar.sundararaju@amd.com"><sathishkumar.sundararaju@amd.com></a> wrote:<br>
                >>>>>> On 8/14/2025 2:33 AM, Alex
                Deucher wrote:<br>
                >>>>>>> On Wed, Aug 13, 2025 at
                4:58 PM Sundararaju, Sathishkumar<br>
                >>>>>>>
                <a class="moz-txt-link-rfc2396E" href="mailto:sathishkumar.sundararaju@amd.com"><sathishkumar.sundararaju@amd.com></a> wrote:<br>
                >>>>>>>> On 8/14/2025 1:35 AM,
                Alex Deucher wrote:<br>
                >>>>>>>>> On Wed, Aug 13,
                2025 at 2:23 PM Sundararaju, Sathishkumar<br>
                >>>>>>>>>
                <a class="moz-txt-link-rfc2396E" href="mailto:sathishkumar.sundararaju@amd.com"><sathishkumar.sundararaju@amd.com></a> wrote:<br>
                >>>>>>>>>> Hi Alex, Hi
                David,<br>
                >>>>>>>>>><br>
                >>>>>>>>>> I see David's
                concern but his suggestion yet wont solve the<br>
                >>>>>>>>>> problem,
                neither the current form , reason :-<br>
                >>>>>>>>>><br>
                >>>>>>>>>> The emitted
                fence count and total submission count are fast<br>
                >>>>>>>>>> transients
                which frequently become 0 in between video decodes<br>
                >>>>>>>>>> (between jobs)
                even with the atomics and locks there can be a<br>
                >>>>>>>>>> switch of video
                power profile, in the current form of patch<br>
                >>>>>>>>>> that window is
                minimized, but still can happen if stress<br>
                >>>>>>>>>> tested. But
                power state of any instance becoming zero<br>
                >>>>>>>>> Can you explain how
                this can happen?  I'm not seeing it.<br>
                >>>>>>>> Consider this
                situation, inst0 and inst1 actively decoding,<br>
                >>>>>>>> inst0 decode completes,
                delayed idle work starts.<br>
                >>>>>>>> inst0 idle handler can
                read 0 total fences and 0 total<br>
                >>>>>>>> submission count, even
                if inst1 is actively decoding, that's between the jobs,<br>
                >>>>>>>>         - as begin_use
                increaments vcn.total_submission_cnt and<br>
                >>>>>>>> end_use decreaments
                vcn.total_submission_cnt that can be 0.<br>
                >>>>>>>>         - if
                outstanding fences are cleared and no new emitted<br>
                >>>>>>>> fence, between jobs ,
                can be 0.<br>
                >>>>>>>>         - both of the
                above conditions do not mean video decode<br>
                >>>>>>>> is complete on inst1,
                it is actively decoding.<br>
                >>>>>>> How can there be active
                decoding without an outstanding fence?<br>
                >>>>>>> In that case, total_fences
                (fences from both instances) would be non-0.<br>
                >>>>>> I mean on inst1 the job
                scheduled is already complete, so 0<br>
                >>>>>> outstanding fences, newer job
                is yet to be scheduled<br>
                >>>>>><br>
                >>>>>> and commited to ring (inst1) ,
                this doesn't mean decode has<br>
                >>>>>> stopped on<br>
                >>>>>> inst1 right (I am saying if
                timing of inst0 idle work coincides<br>
                >>>>>> with this),<br>
                >>>>>><br>
                >>>>>> Or am I wrong in assuming this
                ? Can't this ever happen ? Please<br>
                >>>>>> correct my understanding here.<br>
                >>>>> The flow looks like:<br>
                >>>>><br>
                >>>>> begin_use(inst)<br>
                >>>>> emit_fence(inst)<br>
                >>>>> end_use(inst)<br>
                >>>>><br>
                >>>>> ...later<br>
                >>>>> fence signals<br>
                >>>>> ...later<br>
                >>>>> work handler<br>
                >>>>><br>
                >>>>> In begin_use we increment the
                global and per instance submission.<br>
                >>>>> This protects the power gating and
                profile until end_use.  In end<br>
                >>>>> use we decrement the submissions
                because we don't need to protect<br>
                >>>>> anything any more as we have the
                fence that was submitted via the<br>
                >>>>> ring.  That fence won't signal
                until the job is complete.<br>
                >>>> Is a next begin_use always guaranteed
                to be run before current job fence signals ?<br>
                >>>><br>
                >>>> if not then both total submission and
                total fence are zero , example<br>
                >>>> delayed job/packet submissions<br>
                >>>><br>
                >>>> from user space, or next job schedule
                happens after current job fence signals.<br>
                >>>><br>
                >>>> if this is never possible then (v3) is
                perfect.<br>
                >>>><br>
                >>>> Regards,<br>
                >>>><br>
                >>>> Sathish<br>
                >>>><br>
                >>>>> For power gating, we<br>
                >>>>> only care about the submission
                count and fences for that instance,<br>
                >>>>> for the profile, we care about
                submission count and fences all instances.<br>
                >>>>> Once the fences have signalled, the
                outstanding fences will be 0<br>
                >>>>> and there won't be any active work.<br>
                >>>>><br>
                >>>>> Alex<br>
                >>>>><br>
                >>>>>> Regards,<br>
                >>>>>><br>
                >>>>>> Sathish<br>
                >>>>>><br>
                >>>>>>> Alex<br>
                >>>>>>><br>
                >>>>>>>> Whereas if instances
                are powered off we are sure idle time is<br>
                >>>>>>>> past and it is powered
                off, no possible way of active video<br>
                >>>>>>>> decode, when all
                instances are off we can safely assume no<br>
                >>>>>>>> active decode and
                global lock protects it against new begin_use on any
                instance.<br>
                >>>>>>>> But the only distant
                concern is global common locks w.r.t perf,<br>
                >>>>>>>> but we are already
                having a global workprofile mutex , so there<br>
                >>>>>>>> shouldn't be any drop
                in perf, with just one single global lock<br>
                >>>>>>>> for all instances.<br>
                >>>>>>>><br>
                >>>>>>>> Just sending out a
                patch with this fix, will leave it to you to<br>
                >>>>>>>> decide the right
                method. If you think outstanding total fences<br>
                >>>>>>>> can never be 0 during
                decode, then your previous version (v3)<br>
                >>>>>>>> itself is good, there
                is no real benefit of splitting the handlers as such.<br>
                >>>>>>>><br>
                >>>>>>>> Regards,<br>
                >>>>>>>> Sathish<br>
                >>>>>>>>> If it is possible,
                maybe it would be easier to just split the<br>
                >>>>>>>>> profile and
                powergating into separate handlers.  The profile<br>
                >>>>>>>>> one would be global
                and the powergating one would be per instance.<br>
                >>>>>>>>> See the attached
                patches.<br>
                >>>>>>>>><br>
                >>>>>>>>> Alex<br>
                >>>>>>>>><br>
                >>>>>>>>>> can be a sure
                shot indication of break in a video decode, the<br>
                >>>>>>>>>> mistake in my
                patch was using per instance mutex, I should<br>
                >>>>>>>>>> have used a
                common global mutex, then that covers the situation
                David is trying to bring out.<br>
                >>>>>>>>>><br>
                >>>>>>>>>> Using one
                global vcn.pg_lock for idle and begin_use and using<br>
                >>>>>>>>>> flags to track
                power state could help us totally avoid this situation.<br>
                >>>>>>>>>><br>
                >>>>>>>>>> Regards,<br>
                >>>>>>>>>><br>
                >>>>>>>>>> Sathish<br>
                >>>>>>>>>><br>
                >>>>>>>>>> On 8/13/2025
                11:46 PM, Wu, David wrote:<br>
                >>>>>>>>>>> On
                8/13/2025 12:51 PM, Alex Deucher wrote:<br>
                >>>>>>>>>>>> On Wed,
                Aug 13, 2025 at 12:39 PM Wu, David
                <a class="moz-txt-link-rfc2396E" href="mailto:davidwu2@amd.com"><davidwu2@amd.com></a> wrote:<br>
                >>>>>>>>>>>>> Hi
                Alex,<br>
                >>>>>>>>>>>>><br>
                >>>>>>>>>>>>> The
                addition of  total_submission_cnt should work - in that<br>
                >>>>>>>>>>>>> it
                is unlikely to have a context switch right after the
                begin_use().<br>
                >>>>>>>>>>>>> The
                suggestion of moving it inside the lock (which I prefer<br>
                >>>>>>>>>>>>> in
                case someone adds more before the lock and not reviewed<br>
                >>>>>>>>>>>>>
                thoroughly)<br>
>>>>>>>>>>>>>           - up to
                you to decide.<br>
                >>>>>>>>>>>>><br>
                >>>>>>>>>>>>>
                Reviewed-by: David (Ming Qiang) Wu
                <a class="moz-txt-link-rfc2396E" href="mailto:David.Wu3@amd.com"><David.Wu3@amd.com></a><br>
                >>>>>>>>>>>>><br>
                >>>>>>>>>>>>>
                Thanks,<br>
                >>>>>>>>>>>>>
                David<br>
                >>>>>>>>>>>>> On
                8/13/2025 9:45 AM, Alex Deucher wrote:<br>
                >>>>>>>>>>>>>>
                If there are multiple instances of the VCN running, we
                may<br>
                >>>>>>>>>>>>>>
                end up switching the video profile while another
                instance<br>
                >>>>>>>>>>>>>>
                is active because we only take into account the current<br>
                >>>>>>>>>>>>>>
                instance's submissions.  Look at all outstanding fences<br>
                >>>>>>>>>>>>>>
                for the video profile.<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
                v2: drop early exit in begin_use()<br>
                >>>>>>>>>>>>>>
                v3: handle possible race between begin_use() work
                handler<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
                Fixes: 3b669df92c85 ("drm/amdgpu/vcn: adjust workload<br>
                >>>>>>>>>>>>>>
                profile<br>
                >>>>>>>>>>>>>>
                handling")<br>
                >>>>>>>>>>>>>>
                Reviewed-by: Sathishkumar S<br>
                >>>>>>>>>>>>>>
                <a class="moz-txt-link-rfc2396E" href="mailto:sathishkumar.sundararaju@amd.com"><sathishkumar.sundararaju@amd.com></a> (v1)<br>
                >>>>>>>>>>>>>>
                Signed-off-by: Alex Deucher
                <a class="moz-txt-link-rfc2396E" href="mailto:alexander.deucher@amd.com"><alexander.deucher@amd.com></a><br>
                >>>>>>>>>>>>>>
                ---<br>
>>>>>>>>>>>>>>          
                drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c | 40<br>
                >>>>>>>>>>>>>>
                ++++++++++++-------------<br>
>>>>>>>>>>>>>>          
                drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h |  1 +<br>
>>>>>>>>>>>>>>           2
                files changed, 21 insertions(+), 20<br>
                >>>>>>>>>>>>>>
                deletions(-)<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
                diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c<br>
                >>>>>>>>>>>>>>
                b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c<br>
                >>>>>>>>>>>>>>
                index 9a76e11d1c184..593c1ddf8819b 100644<br>
                >>>>>>>>>>>>>>
                --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c<br>
                >>>>>>>>>>>>>>
                +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.c<br>
                >>>>>>>>>>>>>>
                @@ -415,19 +415,25 @@ static void<br>
                >>>>>>>>>>>>>>
                amdgpu_vcn_idle_work_handler(struct work_struct *work)<br>
>>>>>>>>>>>>>>              
                struct amdgpu_vcn_inst *vcn_inst =<br>
>>>>>>>>>>>>>>                      
                container_of(work, struct<br>
                >>>>>>>>>>>>>>
                amdgpu_vcn_inst, idle_work.work);<br>
>>>>>>>>>>>>>>              
                struct amdgpu_device *adev = vcn_inst->adev;<br>
                >>>>>>>>>>>>>>
                -     unsigned int fences = 0,
                fence[AMDGPU_MAX_VCN_INSTANCES] = {0};<br>
                >>>>>>>>>>>>>>
                -     unsigned int i = vcn_inst->inst, j;<br>
                >>>>>>>>>>>>>>
                +     unsigned int total_fences = 0,<br>
                >>>>>>>>>>>>>>
                fence[AMDGPU_MAX_VCN_INSTANCES] = {0};<br>
                >>>>>>>>>>>>>>
                +     unsigned int i, j;<br>
>>>>>>>>>>>>>>              
                int r = 0;<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
                -     if (adev->vcn.harvest_config & (1 <<
                i))<br>
                >>>>>>>>>>>>>>
                +     if (adev->vcn.harvest_config & (1 <<<br>
                >>>>>>>>>>>>>>
                + vcn_inst->inst))<br>
>>>>>>>>>>>>>>                      
                return;<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
                -     for (j = 0; j <
                adev->vcn.inst[i].num_enc_rings; ++j)<br>
                >>>>>>>>>>>>>>
                -             fence[i] +=<br>
                >>>>>>>>>>>>>>
amdgpu_fence_count_emitted(&vcn_inst->ring_enc[j]);<br>
                >>>>>>>>>>>>>>
                +     for (i = 0; i < adev->vcn.num_vcn_inst; ++i)
                {<br>
                >>>>>>>>>>>>>>
                +             struct amdgpu_vcn_inst *v =<br>
                >>>>>>>>>>>>>>
                + &adev->vcn.inst[i];<br>
                >>>>>>>>>>>>>>
                +<br>
                >>>>>>>>>>>>>>
                +             for (j = 0; j < v->num_enc_rings;
                ++j)<br>
                >>>>>>>>>>>>>>
                +                     fence[i] +=<br>
                >>>>>>>>>>>>>>
                amdgpu_fence_count_emitted(&v->ring_enc[j]);<br>
                >>>>>>>>>>>>>>
                +             fence[i] +=
                amdgpu_fence_count_emitted(&v->ring_dec);<br>
                >>>>>>>>>>>>>>
                +             total_fences += fence[i];<br>
                >>>>>>>>>>>>>>
                +     }<br>
                >>>>>>>>>>>>>><br>
>>>>>>>>>>>>>>              
                /* Only set DPG pause for VCN3 or below, VCN4<br>
                >>>>>>>>>>>>>>
                and above will be handled by FW */<br>
>>>>>>>>>>>>>>              
                if (adev->pg_flags & AMD_PG_SUPPORT_VCN_DPG
                &&<br>
                >>>>>>>>>>>>>>
                -         !adev->vcn.inst[i].using_unified_queue) {<br>
                >>>>>>>>>>>>>>
                +         !vcn_inst->using_unified_queue) {<br>
>>>>>>>>>>>>>>                      
                struct dpg_pause_state new_state;<br>
                >>>>>>>>>>>>>><br>
>>>>>>>>>>>>>>                      
                if (fence[i] || @@ -436,18 +442,18 @@<br>
                >>>>>>>>>>>>>>
                static void amdgpu_vcn_idle_work_handler(struct<br>
                >>>>>>>>>>>>>>
                work_struct<br>
                >>>>>>>>>>>>>>
                *work)<br>
>>>>>>>>>>>>>>                      
                else<br>
>>>>>>>>>>>>>>                              
                new_state.fw_based =<br>
                >>>>>>>>>>>>>>
                VCN_DPG_STATE__UNPAUSE;<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
                -            
                adev->vcn.inst[i].pause_dpg_mode(vcn_inst,
                &new_state);<br>
                >>>>>>>>>>>>>>
                +             vcn_inst->pause_dpg_mode(vcn_inst,<br>
                >>>>>>>>>>>>>>
                + &new_state);<br>
>>>>>>>>>>>>>>               }<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
                -     fence[i] +=
                amdgpu_fence_count_emitted(&vcn_inst->ring_dec);<br>
                >>>>>>>>>>>>>>
                -     fences += fence[i];<br>
                >>>>>>>>>>>>>>
                -<br>
                >>>>>>>>>>>>>>
                -     if (!fences &&
                !atomic_read(&vcn_inst->total_submission_cnt)) {<br>
                >>>>>>>>>>>>>>
                +     if (!fence[vcn_inst->inst] &&<br>
                >>>>>>>>>>>>>>
                !atomic_read(&vcn_inst->total_submission_cnt)) {<br>
                >>>>>>>>>>>>>>
                +             /* This is specific to this instance */<br>
>>>>>>>>>>>>>>                      
                mutex_lock(&vcn_inst->vcn_pg_lock);<br>
>>>>>>>>>>>>>>                      
                vcn_inst->set_pg_state(vcn_inst, AMD_PG_STATE_GATE);<br>
>>>>>>>>>>>>>>                      
                mutex_unlock(&vcn_inst->vcn_pg_lock);<br>
                >>>>>>>>>>>>>>
                mutex_lock(&adev->vcn.workload_profile_mutex);<br>
                >>>>>>>>>>>>>>
                -             if (adev->vcn.workload_profile_active)
                {<br>
                >>>>>>>>>>>>>>
                +             /* This is global and depends on all VCN
                instances */<br>
                >>>>>>>>>>>>>>
                +             if (adev->vcn.workload_profile_active
                &&<br>
                >>>>>>>>>>>>>>
                !total_fences &&<br>
                >>>>>>>>>>>>>>
                + !atomic_read(&adev->vcn.total_submission_cnt))
                {<br>
>>>>>>>>>>>>>>                              
                r =<br>
                >>>>>>>>>>>>>>
                amdgpu_dpm_switch_power_profile(adev,<br>
                >>>>>>>>>>>>>>
                PP_SMC_POWER_PROFILE_VIDEO, false);<br>
>>>>>>>>>>>>>>                              
                if (r) @@ -467,16 +473,10 @@<br>
                >>>>>>>>>>>>>>
                void amdgpu_vcn_ring_begin_use(struct amdgpu_ring *ring)<br>
>>>>>>>>>>>>>>              
                int r = 0;<br>
                >>>>>>>>>>>>>><br>
>>>>>>>>>>>>>>              
                atomic_inc(&vcn_inst->total_submission_cnt);<br>
                >>>>>>>>>>>>>>
                +    
                atomic_inc(&adev->vcn.total_submission_cnt);<br>
                >>>>>>>>>>>>>
                move this addition down inside the mutex lock<br>
                >>>>>>>>>>>>>>
                cancel_delayed_work_sync(&vcn_inst->idle_work);<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
                -     /* We can safely return early here because we've
                cancelled the<br>
                >>>>>>>>>>>>>>
                -      * the delayed work so there is no one else to set
                it to false<br>
                >>>>>>>>>>>>>>
                -      * and we don't care if someone else sets it to
                true.<br>
                >>>>>>>>>>>>>>
                -      */<br>
                >>>>>>>>>>>>>>
                -     if (adev->vcn.workload_profile_active)<br>
                >>>>>>>>>>>>>>
                -             goto pg_lock;<br>
                >>>>>>>>>>>>>>
                -<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
                mutex_lock(&adev->vcn.workload_profile_mutex);<br>
                >>>>>>>>>>>>>
                move to here:<br>
                >>>>>>>>>>>>>
                atomic_inc(&adev->vcn.total_submission_cnt);<br>
                >>>>>>>>>>>>> I
                think this should work for multiple instances.<br>
                >>>>>>>>>>>> Why
                does this need to be protected by the mutex?<br>
                >>>>>>>>>>> hmm.. OK -
                no need and it is actually better before the mutex.<br>
                >>>>>>>>>>> David<br>
                >>>>>>>>>>>> Alex<br>
                >>>>>>>>>>>><br>
                >>>>>>>>>>>>>
                David<br>
>>>>>>>>>>>>>>              
                if (!adev->vcn.workload_profile_active) {<br>
>>>>>>>>>>>>>>                      
                r =<br>
                >>>>>>>>>>>>>>
                amdgpu_dpm_switch_power_profile(adev,<br>
                >>>>>>>>>>>>>>
                PP_SMC_POWER_PROFILE_VIDEO, @@ -487,7 +487,6 @@ void<br>
                >>>>>>>>>>>>>>
                amdgpu_vcn_ring_begin_use(struct amdgpu_ring *ring)<br>
>>>>>>>>>>>>>>               }<br>
                >>>>>>>>>>>>>>
                mutex_unlock(&adev->vcn.workload_profile_mutex);<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
                -pg_lock:<br>
>>>>>>>>>>>>>>              
                mutex_lock(&vcn_inst->vcn_pg_lock);<br>
>>>>>>>>>>>>>>              
                vcn_inst->set_pg_state(vcn_inst,<br>
                >>>>>>>>>>>>>>
                AMD_PG_STATE_UNGATE);<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
                @@ -528,6 +527,7 @@ void amdgpu_vcn_ring_end_use(struct<br>
                >>>>>>>>>>>>>>
                amdgpu_ring<br>
                >>>>>>>>>>>>>>
                *ring)<br>
                >>>>>>>>>>>>>>
atomic_dec(&ring->adev->vcn.inst[ring->me].dpg_enc_submiss<br>
                >>>>>>>>>>>>>>
                i<br>
                >>>>>>>>>>>>>>
                o<br>
                >>>>>>>>>>>>>>
                n<br>
                >>>>>>>>>>>>>>
                _cnt);<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
atomic_dec(&ring->adev->vcn.inst[ring->me].total_submissio<br>
                >>>>>>>>>>>>>>
                n<br>
                >>>>>>>>>>>>>>
                _<br>
                >>>>>>>>>>>>>>
                c<br>
                >>>>>>>>>>>>>>
                nt);<br>
                >>>>>>>>>>>>>>
                +
                atomic_dec(&ring->adev->vcn.total_submission_cnt);<br>
                >>>>>>>>>>>>>><br>
                >>>>>>>>>>>>>>
schedule_delayed_work(&ring->adev->vcn.inst[ring->me].idle_work,<br>
>>>>>>>>>>>>>>                                    
                VCN_IDLE_TIMEOUT); diff<br>
                >>>>>>>>>>>>>>
                --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h<br>
                >>>>>>>>>>>>>>
                b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h<br>
                >>>>>>>>>>>>>>
                index b3fb1d0e43fc9..febc3ce8641ff 100644<br>
                >>>>>>>>>>>>>>
                --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h<br>
                >>>>>>>>>>>>>>
                +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vcn.h<br>
                >>>>>>>>>>>>>>
                @@ -352,6 +352,7 @@ struct amdgpu_vcn {<br>
                >>>>>>>>>>>>>><br>
>>>>>>>>>>>>>>              
                uint16_t inst_mask;<br>
>>>>>>>>>>>>>>              
                uint8_t num_inst_per_aid;<br>
                >>>>>>>>>>>>>>
                +     atomic_t                total_submission_cnt;<br>
                >>>>>>>>>>>>>><br>
>>>>>>>>>>>>>>              
                /* IP reg dump */<br>
>>>>>>>>>>>>>>              
                uint32_t                *ip_dump;<br>
              </div>
            </span></font></div>
      </div>
    </blockquote>
  </body>
</html>