AMDGPU with 4.19.x kernel - cannot enable DPM

[Alex Deucher]

the default is -1 (auto).  Power management has always been enabled by
default on CI.  the option is mainly there to disable power management
(amdgpu.dpm=0).  Since there are two implementations for CI (the older
one ported from radeon and the newer powerplay one), explicitly
setting it to 1 was used to select between the two implementations for
testing purposes.  The default implementation changed.

Alex
On Thu, Dec 6, 2018 at 11:12 AM Chris Rankin <rankincj at gmail.com> wrote:
>
> OK, thanks. Although for reference, if DPM is now enabled by default I would have expected amdgpu.dpm=1 to be a no-op rather than cause a black screen and an oops... ;-).
>
> Cheers,
> Chris
>
> On Thu, 6 Dec 2018 at 16:09, Alex Deucher <alexdeucher at gmail.com> wrote:
>>
>> Then you should be fine to remove it.
>>
>> Alex
>> On Thu, Dec 6, 2018 at 10:58 AM Chris Rankin <rankincj at gmail.com> wrote:
>> >
>> > Yes, all 4.19.x kernels have been fine without the amdgpu.dpm=1 kernel parameter. In fact, this is how I am running my kernel right now. With the 4.18.x series I did specify amdgpu.dpm=1 explicitly on the GRUB2 command line, and I inherited this setting when I migrated to 4.19.
>> >
>> > On Thu, 6 Dec 2018 at 15:53, Alex Deucher <alexdeucher at gmail.com> wrote:
>> >>
>> >> Does it work without amdgpu.dpm=1 on your kernel command line?  You
>> >> don't need to specify it, it;s enabled by default.  The default dpm
>> >> implementation changed so specifying dpm=1 will change the dpm
>> >> implementation used by the driver.
>> >>
>> >> Alex
>> >> On Thu, Dec 6, 2018 at 10:47 AM Alex Deucher <alexdeucher at gmail.com> wrote:
>> >> >
>> >> > I can't reproduce this.  Can you bisect?
>> >> >
>> >> > Alex
>> >> > On Thu, Dec 6, 2018 at 8:38 AM Chris Rankin <rankincj at gmail.com> wrote:
>> >> > >
>> >> > > Hi,
>> >> > >
>> >> > > I'm still unable to enable DPM with my R7 360, AMDGPU driver, Linux 4.19.7 kernel. Dmesg log is attached, showing that it is correctly using PCIE gen2 speeds.
>> >> > >
>> >> > > Cheers,
>> >> > > Chris
>> >> > >
>> >> > > On Sat, 24 Nov 2018 at 13:12, Chris Rankin <rankincj at gmail.com> wrote:
>> >> > >>
>> >> > >> Hi, thanks for the reply.
>> >> > >>
>> >> > >> That patch doesn't solve my issue, although it does mean that the DRM layer no longer tries to enable "gen 3" PCIE link speeds.
>> >> > >> I have attached the dmesg output for a stock 4.19.4 kernel that also has your patch applied.
>> >> > >>
>> >> > >> Cheers,
>> >> > >> Chris
>> >> > >>
>> >> > >> On Fri, 23 Nov 2018 at 20:25, Alex Deucher <alexdeucher at gmail.com> wrote:
>> >> > >>>
>> >> > >>> On Thu, Nov 22, 2018 at 7:23 PM Chris Rankin <rankincj at gmail.com> wrote:
>> >> > >>> >
>> >> > >>> > Hi,
>> >> > >>> >
>> >> > >>> > I have recently tried to use dpm=1 with the amdgpu driver for the 4.19.x kernel, but unfortunately the screen just went black. This is a regression from the 4.18.x kernel.
>> >> > >>> >
>> >> > >>> > I have attached the full dmesg log, but the relevant section look to be:
>> >> > >>> >
>> >> > >>> > [    8.958679] WARNING: CPU: 0 PID: 320 at drivers/gpu/drm/drm_mm.c:950 drm_mm_takedown+0x1f/0x30 [drm]
>> >> > >>> > [    9.010509] Code: f6 c3 48 8d 41 c0 eb bb 0f 1f 00 66 66 66 66 90 48 8b 47 38 48 83 c7 38 48 39 c7 75 01 c3 48 c7 c7 a0 68 26 c0 e8 6b 4d e8 d9 <0f> 0b c3 0f 1f 40 00 66 2e 0f 1f 84 00 00 00 00 00 66 66 66 66 90
>> >> > >>> > [    9.029395] RSP: 0018:ffffae0681e8f9e8 EFLAGS: 00010282
>> >> > >>> > [    9.034681] RAX: 0000000000000000 RBX: ffff91febbb9f900 RCX: 0000000000000000
>> >> > >>> > [    9.041875] RDX: ffff91fec3a1cf00 RSI: ffff91fec3a16868 RDI: ffff91fec3a16868
>> >> > >>> > [    9.049068] RBP: ffff91feb92b29a0 R08: 0000000000000000 R09: ffff91fb800bb480
>> >> > >>> > [    9.056260] R10: ffffffff9a4e7560 R11: ffffffff9b9b616d R12: ffff91feb92b2980
>> >> > >>> > [    9.063454] R13: 0000000000000000 R14: 0000000000000170 R15: ffff91feb938aee0
>> >> > >>> > [    9.070647] FS:  00007f71200ee180(0000) GS:ffff91fec3a00000(0000) knlGS:0000000000000000
>> >> > >>> > [    9.078821] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
>> >> > >>> > [    9.084625] CR2: 00007f8be0615020 CR3: 000000033b014000 CR4: 00000000000006f0
>> >> > >>> >
>> >> > >>>
>> >> > >>> You may need this patch depending on your platform:
>> >> > >>> https://patchwork.freedesktop.org/patch/259364/
>> >> > >>>
>> >> > >>> Alex
>> >> > >>>
>> >> > >>> > Cheers,
>> >> > >>> > Chris
>> >> > >>> >
>> >> > >>> > _______________________________________________
>> >> > >>> > dri-devel mailing list
>> >> > >>> > dri-devel at lists.freedesktop.org
>> >> > >>> > https://lists.freedesktop.org/mailman/listinfo/dri-devel