[Intel-gfx] [Regression] "drm/i915: Implement display w/a #1143" breaks HDMI on ASUS GL552VW

Tue Oct 13 12:25:38 UTC 2020

Hi, 

> -----Original Message-----
> From: Kai-Heng Feng <kai.heng.feng at canonical.com>
> Sent: tiistai 13. lokakuuta 2020 15.18
> To: Saarinen, Jani <jani.saarinen at intel.com>
> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>; intel-gfx <intel-
> gfx at lists.freedesktop.org>; Runyan, Arthur J <arthur.j.runyan at intel.com>
> Subject: Re: [Intel-gfx] [Regression] "drm/i915: Implement display w/a #1143"
> breaks HDMI on ASUS GL552VW
> 
> 
> 
> > On Oct 13, 2020, at 19:50, Saarinen, Jani <jani.saarinen at intel.com> wrote:
> >
> > Hi,
> >> -----Original Message-----
> >> From: Intel-gfx <intel-gfx-bounces at lists.freedesktop.org> On Behalf
> >> Of Ville Syrjälä
> >> Sent: tiistai 13. lokakuuta 2020 14.16
> >> To: Kai-Heng Feng <kai.heng.feng at canonical.com>
> >> Cc: intel-gfx <intel-gfx at lists.freedesktop.org>; Runyan, Arthur J
> >> <arthur.j.runyan at intel.com>
> >> Subject: Re: [Intel-gfx] [Regression] "drm/i915: Implement display w/a
> #1143"
> >> breaks HDMI on ASUS GL552VW
> >>
> >> On Tue, Oct 13, 2020 at 01:20:35PM +0800, Kai-Heng Feng wrote:
> >>>
> >>>
> >>>> On Sep 3, 2020, at 14:26, Kai-Heng Feng
> >>>> <kai.heng.feng at canonical.com>
> >> wrote:
> >>>>
> >>>>
> >>>>
> >>>>> On Aug 26, 2020, at 21:05, Ville Syrjälä
> >>>>> <ville.syrjala at linux.intel.com>
> >> wrote:
> >>>>>
> >>>>> On Wed, Aug 26, 2020 at 12:40:15PM +0800, Kai-Heng Feng wrote:
> >>>>>> Hi,
> >>>>>>
> >>>>>>> On Aug 25, 2020, at 02:46, Runyan, Arthur J
> >> <arthur.j.runyan at intel.com> wrote:
> >>>>>>>
> >>>>>>> I remember some strangeness about the blnclegdisbl.  I'll see if
> >>>>>>> I can dig
> >> up some more.
> >>>>>>
> >>>>>>
> >>>>>> The register read can be found at [1] and [2].
> >>>>>>
> >>>>>> [1]
> >>>>>>
> >> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1871721/comme
> >>>>>> nts/119 [2]
> >>>>>>
> >> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1871721/comme
> >>>>>> nts/120
> >>>>>
> >>>>> Looks like it's using the 400mV/0dB setting. Can we get the same
> >>>>> dumps with the driver loaded just to confirm whether we're using
> >>>>> different settings?
> >>>>>
> >>>>> Also a dump of /sys/kernel/debug/dri/0/i915_vbt would be good to
> >>>>> have.
> >>>>
> >>>>
> >>
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1871721/comment
> >>>> s/124
> >>>>
> >>
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1871721/comment
> >>>> s/125
> >>>>
> >>
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1871721/comment
> >>>> s/126
> >>>
> >>> A gentle ping...
> >>
> >> I cooked up some hacks for you to try:
> >> git://github.com/vsyrjala/linux.git skl_vswing_wa_hacks
> >>
> >> An upstream bug report would probably be a good idea so that the
> >> communication doesn't have to go through a middle man over email...
> > Agree, please make gitlab issue on this.
> 
> It was filed two months ago: 
> https://gitlab.freedesktop.org/drm/intel/-/issues/2181
Sigh, thanks. 

> 
> 
> >
> >>
> >>>
> >>>>
> >>>> Kai-Heng
> >>>>
> >>>>>
> >>>>>>
> >>>>>> Kai-Heng
> >>>>>>
> >>>>>>>
> >>>>>>> -----Original Message-----
> >>>>>>> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> >>>>>>> Sent: Monday, August 24, 2020 11:05 AM
> >>>>>>> To: Kai-Heng Feng <kai.heng.feng at canonical.com>
> >>>>>>> Cc: Runyan, Arthur J <arthur.j.runyan at intel.com>; Vivi, Rodrigo
> >>>>>>> <rodrigo.vivi at intel.com>; intel-gfx
> >>>>>>> <intel-gfx at lists.freedesktop.org>
> >>>>>>> Subject: Re: [Regression] "drm/i915: Implement display w/a #1143"
> >>>>>>> breaks HDMI on ASUS GL552VW
> >>>>>>>
> >>>>>>> On Mon, Aug 17, 2020 at 02:17:49PM +0800, Kai-Heng Feng wrote:
> >>>>>>>>
> >>>>>>>>
> >>>>>>>>> On Aug 17, 2020, at 00:22, Runyan, Arthur J
> >> <arthur.j.runyan at intel.com> wrote:
> >>>>>>>>>
> >>>>>>>>> You'll need to read out the DDI_BUF_TRANS_* and
> >> DISPIO_CR_TX_BMU_CR0 registers at boot before i915 programs them and
> >> compare with what driver programs.
> >>>>>>>>> Rodrigo can probably show you how.
> >>>>>>>>
> >>>>>>>> Right, I'll wait for a patch then :)
> >>>>>>>
> >>>>>>> To grab the BIOS reg values we just have to make sure the driver
> >>>>>>> doesn't
> >> load. Eg. pass something like "modprobe.blacklist=i915,snd_hda_intel
> >> 3" to the kernel cmdline (+ whatever other magic ubuntu might
> >> require). Confirm with something like "lsmod | grep i915" to make
> >> sure the driver didn't sneak in despite our best efforts.
> >>>>>>>
> >>>>>>> Then we can dump the registers with intel_reg from igt-gpu-tools:
> >>>>>>> intel_reg read --count 20 0x64E00 0x64E60 0x64EC0 0x64F20
> >>>>>>> 0x64F80 intel_reg read 0x64000 0x64100 0x64200 0x64300 0x64400
> >>>>>>> 0x6C00C
> >>>>>>>
> >>>>>>> The only somewhat suspicious thing I noticed is that we treat
> >> DISPIO_CR_TX_BMU_CR0:tx_blnclegdisbl as a bitmask (bit 23 -> DDI A,
> >> bit 24 -> DDI B, etc.) whereas the spec seems to be saying that we
> >> should just zero out all the bits of tx_blnclegdisbl when any DDI
> >> needs iboost. Art, is our interpretation of the bits correct or just a fairy tale?
> >>>>>>>
> >>>>>>>>
> >>>>>>>> Kai-Heng
> >>>>>>>>
> >>>>>>>>>
> >>>>>>>>> -----Original Message-----
> >>>>>>>>> From: Kai-Heng Feng <kai.heng.feng at canonical.com>
> >>>>>>>>> Sent: Thursday, August 13, 2020 10:14 PM
> >>>>>>>>> To: Runyan, Arthur J <arthur.j.runyan at intel.com>
> >>>>>>>>> Cc: Vivi, Rodrigo <rodrigo.vivi at intel.com>; Ville Syrjälä
> >>>>>>>>> <ville.syrjala at linux.intel.com>; intel-gfx
> >>>>>>>>> <intel-gfx at lists.freedesktop.org>
> >>>>>>>>> Subject: Re: [Regression] "drm/i915: Implement display w/a
> #1143"
> >>>>>>>>> breaks HDMI on ASUS GL552VW
> >>>>>>>>>
> >>>>>>>>> Hi,
> >>>>>>>>>
> >>>>>>>>>> On Aug 14, 2020, at 01:56, Runyan, Arthur J
> >> <arthur.j.runyan at intel.com> wrote:
> >>>>>>>>>>
> >>>>>>>>>> The workaround is freeing up stuck vswing values to let new
> >>>>>>>>>> vswing
> >> programming kick in.  Maybe the new vswing values are wrong.
> >>>>>>>>>> Try checking the vswing that driver programs against what
> >> BIOS/GOP programs.
> >>>>>>>>>
> >>>>>>>>> Do you mean to print out value of I915_READ()?
> >>>>>>>>> val = I915_READ(CHICKEN_TRANS(transcoder));
> >>>>>>>>>
> >>>>>>>>> Kai-Heng
> >>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>> -----Original Message-----
> >>>>>>>>>> From: Vivi, Rodrigo <rodrigo.vivi at intel.com>
> >>>>>>>>>> Sent: Thursday, August 13, 2020 9:50 AM
> >>>>>>>>>> To: Kai-Heng Feng <kai.heng.feng at canonical.com>; Runyan,
> >>>>>>>>>> Arthur J <arthur.j.runyan at intel.com>
> >>>>>>>>>> Cc: Ville Syrjälä <ville.syrjala at linux.intel.com>; intel-gfx
> >>>>>>>>>> <intel-gfx at lists.freedesktop.org>
> >>>>>>>>>> Subject: Re: [Regression] "drm/i915: Implement display w/a
> #1143"
> >>>>>>>>>> breaks HDMI on ASUS GL552VW
> >>>>>>>>>>
> >>>>>>>>>> Art, any comment here?
> >>>>>>>>>>
> >>>>>>>>>> I just checked and the  W/a 1143 is implemented as described,
> >>>>>>>>>> but it
> >> is failing HDMI on this hybrid system.
> >>>>>>>>>>
> >>>>>>>>>>> On Aug 12, 2020, at 9:07 PM, Kai-Heng Feng
> >> <kai.heng.feng at canonical.com> wrote:
> >>>>>>>>>>>
> >>>>>>>>>>> Hi,
> >>>>>>>>>>>
> >>>>>>>>>>> There's a regression reported that HDMI output stops working
> >> after os upgrade:
> >>>>>>>>>>> https://bugs.launchpad.net/bugs/1871721
> >>>>>>>>>>>
> >>>>>>>>>>> Here's the bisect result:
> >>>>>>>>>>> 0519c102f5285476d7868a387bdb6c58385e4074 is the first bad
> >>>>>>>>>>> commit commit
> 0519c102f5285476d7868a387bdb6c58385e4074
> >>>>>>>>>>> Author: Ville Syrjälä <ville.syrjala at linux.intel.com>
> >>>>>>>>>>> Date:   Mon Jan 22 19:41:31 2018 +0200
> >>>>>>>>>>>
> >>>>>>>>>>> drm/i915: Implement display w/a #1143
> >>>>>>>>>>>
> >>>>>>>>>>> Apparently SKL/KBL/CFL need some manual help to get the
> >>>>>>>>>>> programmed HDMI vswing to stick. Implement the relevant
> >>>>>>>>>>> workaround (display w/a #1143).
> >>>>>>>>>>>
> >>>>>>>>>>> Note that the relevant chicken bits live in a transcoder
> >>>>>>>>>>> register even though the bits affect a specific DDI port
> >>>>>>>>>>> rather than a specific transcoder. Hence we must pick the
> >>>>>>>>>>> correct transcoder register instance based on the port
> >>>>>>>>>>> rather than based on the cpu_transcoder.
> >>>>>>>>>>>
> >>>>>>>>>>> Also note that for completeness I included support for DDI
> >>>>>>>>>>> A/E in the code even though we never have HDMI on those
> ports.
> >>>>>>>>>>>
> >>>>>>>>>>> v2: CFL needs the w/a as well (Rodrigo and Art)
> >>>>>>>>>>>
> >>>>>>>>>>> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> >>>>>>>>>>> Cc: Art Runyan <arthur.j.runyan at intel.com>
> >>>>>>>>>>> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
> >>>>>>>>>>> Link:
> >>>>>>>>>>>
> >> https://patchwork.freedesktop.org/patch/msgid/20180122174131.
> >>>>>>>>>>> 28046 -1-ville.syrjala at linux.intel.com
> >>>>>>>>>>> Reviewed-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> >>>>>>>>>>>
> >>>>>>>>>>>
> >>>>>>>>>>> dmesg from drm-tip with drm.debug=0xe can be found here:
> >>>>>>>>>>>
> >> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1871721/
> >>>>>>>>>>> comme
> >>>>>>>>>>> nts
> >>>>>>>>>>> /
> >>>>>>>>>>> 64
> >>>>>>>>>>>
> >>>>>>>>>>> Kai-Heng
> >>>>>>>>>>
> >>>>>>>>>>
> >>>>>>>>>
> >>>>>>>
> >>>>>>> --
> >>>>>>> Ville Syrjälä
> >>>>>>> Intel
> >>>>>
> >>>>> --
> >>>>> Ville Syrjälä
> >>>>> Intel
> >>>>
> >>
> >> --
> >> Ville Syrjälä
> >> Intel
> >> _______________________________________________
> >> Intel-gfx mailing list
> >> Intel-gfx at lists.freedesktop.org
> >> https://lists.freedesktop.org/mailman/listinfo/intel-gfx