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Re: Bad flicker on skylake HQD due to code in the 4.7 merge window

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  Re: Bad flicker on skylake HQD due to code in the 4.7 merge window Jani Nikula <jani.nikula@linux.intel.com> - 2016-06-13 12:20 +0200
    Re: Bad flicker on skylake HQD due to code in the 4.7 merge window James Bottomley <James.Bottomley@HansenPartnership.com> - 2016-06-16 23:20 +0200
      Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7  merge window Daniel Vetter <daniel@ffwll.ch> - 2016-06-16 23:30 +0200
        Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7  merge window James Bottomley <James.Bottomley@HansenPartnership.com> - 2016-06-17 00:50 +0200
          Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7  merge window Daniel Vetter <daniel@ffwll.ch> - 2016-06-17 09:30 +0200
            Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window Jani Nikula <jani.nikula@linux.intel.com> - 2016-06-17 15:40 +0200
              Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7  merge window James Bottomley <James.Bottomley@HansenPartnership.com> - 2016-06-17 18:10 +0200
              Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7  merge window James Bottomley <James.Bottomley@HansenPartnership.com> - 2016-06-18 01:10 +0200
                Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7  merge window James Bottomley <James.Bottomley@HansenPartnership.com> - 2016-06-20 00:20 +0200
                  Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window Jani Nikula <jani.nikula@linux.intel.com> - 2016-06-20 10:10 +0200
                    Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7  merge window Ville Syrjälä <ville.syrjala@linux.intel.com> - 2016-06-21 17:50 +0200
                      Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7  merge window James Bottomley <James.Bottomley@HansenPartnership.com> - 2016-06-21 23:10 +0200
                        Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7  merge window James Bottomley <James.Bottomley@HansenPartnership.com> - 2016-06-23 13:30 +0200
                  Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7  merge window Steven Newbury <steve@snewbury.org.uk> - 2016-06-23 15:00 +0200
                    Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window Jani Nikula <jani.nikula@linux.intel.com> - 2016-06-23 15:00 +0200
                      Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7  merge window Steven Newbury <steve@snewbury.org.uk> - 2016-06-23 15:20 +0200
        Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7  merge window Chris Wilson <chris@chris-wilson.co.uk> - 2016-06-17 10:20 +0200

#1420681 — Re: Bad flicker on skylake HQD due to code in the 4.7 merge window

On Tue, 31 May 2016, James Bottomley <James.Bottomley@HansenPartnership.com> wrote:
> On Tue, 2016-05-31 at 10:51 +0300, Jani Nikula wrote:
>> On Mon, 30 May 2016, James Bottomley <
>> James.Bottomley@HansenPartnership.com> wrote:
>> > I've tested a pristine 4.6.0 system, so it's definitely something
>> > that
>> > went in during the merge window.  The flicker isn't continuous,
>> > it's
>> > periodic, with an interval of something like 2-5 seconds.  It looks
>> > like an old analogue TV going out of sync and then resyncing.  I've
>> > attached the dmesg and X.org log below just in case they can help. 
>> >  I
>> > might be able to bisect this next week, but, unfortunately, this is
>> > my
>> > current laptop and I'm travelling this week.
>> 
>> Please try i915.enable_psr=0 module parameter.
>
> Makes no discernable difference.  Current parameter settings are:

Sorry for the silence. Would you mind trying out drm-intel-nightly
branch of [1]?

BR,
Jani.

[1] http://cgit.freedesktop.org/drm-intel


-- 
Jani Nikula, Intel Open Source Technology Center

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#1424402

On Mon, 2016-06-13 at 13:14 +0300, Jani Nikula wrote:
> On Tue, 31 May 2016, James Bottomley <
> James.Bottomley@HansenPartnership.com> wrote:
> > On Tue, 2016-05-31 at 10:51 +0300, Jani Nikula wrote:
> > > On Mon, 30 May 2016, James Bottomley <
> > > James.Bottomley@HansenPartnership.com> wrote:
> > > > I've tested a pristine 4.6.0 system, so it's definitely
> > > > something
> > > > that
> > > > went in during the merge window.  The flicker isn't continuous,
> > > > it's
> > > > periodic, with an interval of something like 2-5 seconds.  It
> > > > looks
> > > > like an old analogue TV going out of sync and then resyncing. 
> > > >  I've
> > > > attached the dmesg and X.org log below just in case they can
> > > > help. 
> > > >  I
> > > > might be able to bisect this next week, but, unfortunately,
> > > > this is
> > > > my
> > > > current laptop and I'm travelling this week.
> > > 
> > > Please try i915.enable_psr=0 module parameter.
> > 
> > Makes no discernable difference.  Current parameter settings are:
> 
> Sorry for the silence. Would you mind trying out drm-intel-nightly
> branch of [1]?
> 
> BR,
> Jani.
> 
> [1] http://cgit.freedesktop.org/drm-intel

No, flicker is still there (and in fact seems worse) with the tree with
this commit at the top:

commit 3eb202ecc3668583f9ff4338211dbab47d755d1c
Author: Daniel Vetter <daniel.vetter@ffwll.ch>
Date:   Thu Jun 16 14:38:54 2016 +0200

    drm-intel-nightly: 2016y-06m-16d-12h-38m-37s UTC integration
manifest

James

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#1424423 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Thu, Jun 16, 2016 at 11:15 PM, James Bottomley
<James.Bottomley@hansenpartnership.com> wrote:
> On Mon, 2016-06-13 at 13:14 +0300, Jani Nikula wrote:
>> On Tue, 31 May 2016, James Bottomley <
>> James.Bottomley@HansenPartnership.com> wrote:
>> > On Tue, 2016-05-31 at 10:51 +0300, Jani Nikula wrote:
>> > > On Mon, 30 May 2016, James Bottomley <
>> > > James.Bottomley@HansenPartnership.com> wrote:
>> > > > I've tested a pristine 4.6.0 system, so it's definitely
>> > > > something
>> > > > that
>> > > > went in during the merge window.  The flicker isn't continuous,
>> > > > it's
>> > > > periodic, with an interval of something like 2-5 seconds.  It
>> > > > looks
>> > > > like an old analogue TV going out of sync and then resyncing.
>> > > >  I've
>> > > > attached the dmesg and X.org log below just in case they can
>> > > > help.
>> > > >  I
>> > > > might be able to bisect this next week, but, unfortunately,
>> > > > this is
>> > > > my
>> > > > current laptop and I'm travelling this week.
>> > >
>> > > Please try i915.enable_psr=0 module parameter.
>> >
>> > Makes no discernable difference.  Current parameter settings are:
>>
>> Sorry for the silence. Would you mind trying out drm-intel-nightly
>> branch of [1]?
>>
>> BR,
>> Jani.
>>
>> [1] http://cgit.freedesktop.org/drm-intel
>
> No, flicker is still there (and in fact seems worse) with the tree with
> this commit at the top:
>
> commit 3eb202ecc3668583f9ff4338211dbab47d755d1c
> Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> Date:   Thu Jun 16 14:38:54 2016 +0200
>
>     drm-intel-nightly: 2016y-06m-16d-12h-38m-37s UTC integration
> manifest

Strange indeed, I hoped the improved watermark code in -nightly would
help. I assume nothing in dmesg about underruns or something similar?
I guess we'll need the bisect on this one to make progress.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch

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#1424516 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Thu, 2016-06-16 at 14:29 -0700, James Bottomley wrote:
> On Thu, 2016-06-16 at 23:24 +0200, Daniel Vetter wrote:
> > I guess we'll need the bisect on this one to make progress.
> 
> Sigh, I was afraid that might be the next step.

OK, I have a curious data point.  I assumed the problem would be
somewhere in the drm update, so I started bisecting that at the top. 
 However, the top most commit:

commit 1d6da87a3241deb13d073c4125d19ed0e5a0c62c
Merge: 1f40c49 a39ed68
Author: Linus Torvalds <torvalds@linux-foundation.org>
Date:   Mon May 23 11:48:48 2016 -0700

    Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux

Isn't actually bad.  There's no flicker here, so whatever caused the
problem came from some update after this.

James

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#1424738 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Thu, Jun 16, 2016 at 03:42:12PM -0700, James Bottomley wrote:
> On Thu, 2016-06-16 at 14:29 -0700, James Bottomley wrote:
> > On Thu, 2016-06-16 at 23:24 +0200, Daniel Vetter wrote:
> > > I guess we'll need the bisect on this one to make progress.
> > 
> > Sigh, I was afraid that might be the next step.
> 
> OK, I have a curious data point.  I assumed the problem would be
> somewhere in the drm update, so I started bisecting that at the top. 
>  However, the top most commit:
> 
> commit 1d6da87a3241deb13d073c4125d19ed0e5a0c62c
> Merge: 1f40c49 a39ed68
> Author: Linus Torvalds <torvalds@linux-foundation.org>
> Date:   Mon May 23 11:48:48 2016 -0700
> 
>     Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux
> 
> Isn't actually bad.  There's no flicker here, so whatever caused the
> problem came from some update after this.

There was a fixes pull after this. Might be worth it to restrict to just
the i915 changes, which are just 5b4fd5b1111b1230cd037..157d2c7fad0863222

Looking at those nothing seems to stick out which might explain what's
happening for you.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch

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#1425082 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Fri, 17 Jun 2016, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Thu, Jun 16, 2016 at 03:42:12PM -0700, James Bottomley wrote:
>> On Thu, 2016-06-16 at 14:29 -0700, James Bottomley wrote:
>> > On Thu, 2016-06-16 at 23:24 +0200, Daniel Vetter wrote:
>> > > I guess we'll need the bisect on this one to make progress.
>> > 
>> > Sigh, I was afraid that might be the next step.
>> 
>> OK, I have a curious data point.  I assumed the problem would be
>> somewhere in the drm update, so I started bisecting that at the top. 
>>  However, the top most commit:
>> 
>> commit 1d6da87a3241deb13d073c4125d19ed0e5a0c62c
>> Merge: 1f40c49 a39ed68
>> Author: Linus Torvalds <torvalds@linux-foundation.org>
>> Date:   Mon May 23 11:48:48 2016 -0700
>> 
>>     Merge branch 'drm-next' of git://people.freedesktop.org/~airlied/linux
>> 
>> Isn't actually bad.  There's no flicker here, so whatever caused the
>> problem came from some update after this.
>
> There was a fixes pull after this. Might be worth it to restrict to just
> the i915 changes, which are just 5b4fd5b1111b1230cd037..157d2c7fad0863222
>
> Looking at those nothing seems to stick out which might explain what's
> happening for you.

This should be easy enough to try before bisecting:
http://patchwork.freedesktop.org/patch/msgid/1466162081-12042-1-git-send-email-mika.kahola@intel.com

BR,
Jani.


-- 
Jani Nikula, Intel Open Source Technology Center

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#1425278 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Fri, 2016-06-17 at 16:34 +0300, Jani Nikula wrote:
> On Fri, 17 Jun 2016, Daniel Vetter <daniel@ffwll.ch> wrote:
> > On Thu, Jun 16, 2016 at 03:42:12PM -0700, James Bottomley wrote:
> > > On Thu, 2016-06-16 at 14:29 -0700, James Bottomley wrote:
> > > > On Thu, 2016-06-16 at 23:24 +0200, Daniel Vetter wrote:
> > > > > I guess we'll need the bisect on this one to make progress.
> > > > 
> > > > Sigh, I was afraid that might be the next step.
> > > 
> > > OK, I have a curious data point.  I assumed the problem would be
> > > somewhere in the drm update, so I started bisecting that at the
> > > top. 
> > >  However, the top most commit:
> > > 
> > > commit 1d6da87a3241deb13d073c4125d19ed0e5a0c62c
> > > Merge: 1f40c49 a39ed68
> > > Author: Linus Torvalds <torvalds@linux-foundation.org>
> > > Date:   Mon May 23 11:48:48 2016 -0700
> > > 
> > >     Merge branch 'drm-next' of
> > > git://people.freedesktop.org/~airlied/linux
> > > 
> > > Isn't actually bad.  There's no flicker here, so whatever caused
> > > the
> > > problem came from some update after this.
> > 
> > There was a fixes pull after this. Might be worth it to restrict to
> > just
> > the i915 changes, which are just
> > 5b4fd5b1111b1230cd037..157d2c7fad0863222
> > 
> > Looking at those nothing seems to stick out which might explain
> > what's
> > happening for you.
> 
> This should be easy enough to try before bisecting:
> http://patchwork.freedesktop.org/patch/msgid/1466162081-12042-1-git-s
> end-email-mika.kahola@intel.com

I'll try that.  You should know this platform has a firmware bug in the
digital signals across the display port ... some problem with the mux
in the thunderbolt.  Unfortunately the microcode update for this (the
thunderbolt firmware) can't be applied from Linux or even the usual
FreeDOS, so I'm a bit stuck.

It's also been pointed out to me off list that there's a lot of Skylake
errata that have display flicker due to non-graphics issues:

http://www.intel.com/content/www/us/en/processors/core/desktop-6th-gen-core-family-spec-update.html

My system is a Dell XPS 9350 and I have updated it with the just released firmware:

http://www.dell.com/support/home/us/en/19/Drivers/DriversDetails?driverId=VNT5J

Which causes my cpu microcode version to go from

> [    2.314472] microcode: CPU0 sig=0x406e3, pf=0x80, revision=0x82

to

> [    2.264669] microcode: CPU0 sig=0x406e3, pf=0x80, revision=0x8a

But thanks to the completely opaque microcode update process via the
OEMs it's not clear whether this is sufficient to fix the errata that
are listed as causing flicker (the reported revision on current skylake
lenovos seems to be 0x94)

James

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#1425547 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Fri, 2016-06-17 at 16:34 +0300, Jani Nikula wrote:
> On Fri, 17 Jun 2016, Daniel Vetter <daniel@ffwll.ch> wrote:
> > On Thu, Jun 16, 2016 at 03:42:12PM -0700, James Bottomley wrote:
> > > On Thu, 2016-06-16 at 14:29 -0700, James Bottomley wrote:
> > > > On Thu, 2016-06-16 at 23:24 +0200, Daniel Vetter wrote:
> > > > > I guess we'll need the bisect on this one to make progress.
> > > > 
> > > > Sigh, I was afraid that might be the next step.
> > > 
> > > OK, I have a curious data point.  I assumed the problem would be
> > > somewhere in the drm update, so I started bisecting that at the
> > > top. 
> > >  However, the top most commit:
> > > 
> > > commit 1d6da87a3241deb13d073c4125d19ed0e5a0c62c
> > > Merge: 1f40c49 a39ed68
> > > Author: Linus Torvalds <torvalds@linux-foundation.org>
> > > Date:   Mon May 23 11:48:48 2016 -0700
> > > 
> > >     Merge branch 'drm-next' of
> > > git://people.freedesktop.org/~airlied/linux
> > > 
> > > Isn't actually bad.  There's no flicker here, so whatever caused
> > > the
> > > problem came from some update after this.
> > 
> > There was a fixes pull after this. Might be worth it to restrict to
> > just
> > the i915 changes, which are just
> > 5b4fd5b1111b1230cd037..157d2c7fad0863222
> > 
> > Looking at those nothing seems to stick out which might explain
> > what's
> > happening for you.

OK, so just on the firmware, the system seems less flickery with the
new 1.4.3 UEFI, so I'm starting to think it is a Skylake errata issue. 
 The flicker isn't gone for good, but seems to be reboot dependent
(it's there in some boots, but gone on a reboot).

> This should be easy enough to try before bisecting:
> http://patchwork.freedesktop.org/patch/msgid/1466162081-12042-1-git-s
> end-email-mika.kahola@intel.com

Applying this didn't seem to make a difference: still there on some and
gone on other reboots.

James

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#1426049 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Fri, 2016-06-17 at 16:06 -0700, James Bottomley wrote:
> On Fri, 2016-06-17 at 16:34 +0300, Jani Nikula wrote:
> > On Fri, 17 Jun 2016, Daniel Vetter <daniel@ffwll.ch> wrote:
> > > On Thu, Jun 16, 2016 at 03:42:12PM -0700, James Bottomley wrote:
> > > > On Thu, 2016-06-16 at 14:29 -0700, James Bottomley wrote:
> > > > > On Thu, 2016-06-16 at 23:24 +0200, Daniel Vetter wrote:
> > > > > > I guess we'll need the bisect on this one to make progress.
> > > > > 
> > > > > Sigh, I was afraid that might be the next step.
> > > > 
> > > > OK, I have a curious data point.  I assumed the problem would
> > > > be
> > > > somewhere in the drm update, so I started bisecting that at the
> > > > top. 
> > > >  However, the top most commit:
> > > > 
> > > > commit 1d6da87a3241deb13d073c4125d19ed0e5a0c62c
> > > > Merge: 1f40c49 a39ed68
> > > > Author: Linus Torvalds <torvalds@linux-foundation.org>
> > > > Date:   Mon May 23 11:48:48 2016 -0700
> > > > 
> > > >     Merge branch 'drm-next' of
> > > > git://people.freedesktop.org/~airlied/linux
> > > > 
> > > > Isn't actually bad.  There's no flicker here, so whatever
> > > > caused
> > > > the
> > > > problem came from some update after this.
> > > 
> > > There was a fixes pull after this. Might be worth it to restrict
> > > to
> > > just
> > > the i915 changes, which are just
> > > 5b4fd5b1111b1230cd037..157d2c7fad0863222
> > > 
> > > Looking at those nothing seems to stick out which might explain
> > > what's
> > > happening for you.
> 
> OK, so just on the firmware, the system seems less flickery with the
> new 1.4.3 UEFI, so I'm starting to think it is a Skylake errata 
> issue.  The flicker isn't gone for good, but seems to be reboot 
> dependent (it's there in some boots, but gone on a reboot).
> 
> > This should be easy enough to try before bisecting:
> > http://patchwork.freedesktop.org/patch/msgid/1466162081-12042-1-git
> > -s
> > end-email-mika.kahola@intel.com
> 
> Applying this didn't seem to make a difference: still there on some 
> and gone on other reboots.

OK, my candidate bad commit is this one:

commit a05628195a0d9f3173dd9aa76f482aef692e46ee
Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
Date:   Mon Apr 11 10:23:51 2016 +0300

    drm/i915: Get panel_type from OpRegion panel details

After being more careful about waiting to identify flicker, this one
seems to be the one the bisect finds.  I'm now running v4.7-rc3 with
this one reverted and am currently seeing no flicker problems.  It is,
however, early days because the flicker can hide for long periods, so I
'll wait until Monday evening and a few reboots before declaring
victory.

James

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#1426305 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

Cc: Ville

On Mon, 20 Jun 2016, James Bottomley <James.Bottomley@HansenPartnership.com> wrote:
> OK, my candidate bad commit is this one:
>
> commit a05628195a0d9f3173dd9aa76f482aef692e46ee
> Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Date:   Mon Apr 11 10:23:51 2016 +0300
>
>     drm/i915: Get panel_type from OpRegion panel details
>
> After being more careful about waiting to identify flicker, this one
> seems to be the one the bisect finds.  I'm now running v4.7-rc3 with
> this one reverted and am currently seeing no flicker problems.  It is,
> however, early days because the flicker can hide for long periods, so I
> 'll wait until Monday evening and a few reboots before declaring
> victory.

If that turns out to be the bad commit, it doesn't really surprise me,
and that in itself is depressing.

It might be helpful if you could add drm.debug=14 module parameter, and
provide dmesgs from boot both with and without the above commit (it's
enough to see i915 load). Please also provide
/sys/kernel/debug/dri/0/i915_opregion.

BR,
Jani.

-- 
Jani Nikula, Intel Open Source Technology Center

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#1427889 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Tue, Jun 21, 2016 at 09:53:15AM -0400, James Bottomley wrote:
> On Mon, 2016-06-20 at 11:03 +0300, Jani Nikula wrote:
> > Cc: Ville
> > 
> > On Mon, 20 Jun 2016, James Bottomley <
> > James.Bottomley@HansenPartnership.com> wrote:
> > > OK, my candidate bad commit is this one:
> > > 
> > > commit a05628195a0d9f3173dd9aa76f482aef692e46ee
> > > Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > Date:   Mon Apr 11 10:23:51 2016 +0300
> > > 
> > >     drm/i915: Get panel_type from OpRegion panel details
> > > 
> > > After being more careful about waiting to identify flicker, this 
> > > one seems to be the one the bisect finds.  I'm now running v4.7-rc3
> > > with this one reverted and am currently seeing no flicker problems.
> > >   It is, however, early days because the flicker can hide for long 
> > > periods, so I 'll wait until Monday evening and a few reboots 
> > > before declaring victory.
> > 
> > If that turns out to be the bad commit, it doesn't really surprise 
> > me, and that in itself is depressing.
> 
> As far as I can tell, after running for a day with this reverted, this
> is the problem.  The flicker hasn't appeared with it reverted.  It's
> pretty noticeable with this commit included.

Hmm. The only difference I can see is low vs. normal vswing. Panel 0 has
low, panel 2 has normal. So either the VBT or opregion is telling utter
lies, or there's some other bug in our low vswing support.

To confirm it's really a vswing issue, you should be able to run with
i915.edp_vswing=2 without flickers on the broken kernel.

-- 
Ville Syrjälä
Intel OTC

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#1428162 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Tue, 2016-06-21 at 18:44 +0300, Ville Syrjälä wrote:
> On Tue, Jun 21, 2016 at 09:53:15AM -0400, James Bottomley wrote:
> > On Mon, 2016-06-20 at 11:03 +0300, Jani Nikula wrote:
> > > Cc: Ville
> > > 
> > > On Mon, 20 Jun 2016, James Bottomley <
> > > James.Bottomley@HansenPartnership.com> wrote:
> > > > OK, my candidate bad commit is this one:
> > > > 
> > > > commit a05628195a0d9f3173dd9aa76f482aef692e46ee
> > > > Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > Date:   Mon Apr 11 10:23:51 2016 +0300
> > > > 
> > > >     drm/i915: Get panel_type from OpRegion panel details
> > > > 
> > > > After being more careful about waiting to identify flicker, 
> > > > this one seems to be the one the bisect finds.  I'm now running 
> > > > v4.7-rc3 with this one reverted and am currently seeing no 
> > > > flicker problems.   It is, however, early days because the 
> > > > flicker can hide for long periods, so I 'll wait until Monday 
> > > > evening and a few reboots before declaring victory.
> > > 
> > > If that turns out to be the bad commit, it doesn't really 
> > > surprise me, and that in itself is depressing.
> > 
> > As far as I can tell, after running for a day with this reverted, 
> > this is the problem.  The flicker hasn't appeared with it reverted.
> >  It's pretty noticeable with this commit included.
> 
> Hmm. The only difference I can see is low vs. normal vswing. Panel 0 
> has low, panel 2 has normal. So either the VBT or opregion is telling
> utter lies, or there's some other bug in our low vswing support.
> 
> To confirm it's really a vswing issue, you should be able to run with
> i915.edp_vswing=2 without flickers on the broken kernel.

Preliminary boot indicates no flicker with the bad commit included and
this option, but I'll have to run for quite a bit longer to verify,
since it can sometimes be elusive.

James

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#1429687 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Tue, 2016-06-21 at 17:00 -0400, James Bottomley wrote:
> On Tue, 2016-06-21 at 18:44 +0300, Ville Syrjälä wrote:
> > On Tue, Jun 21, 2016 at 09:53:15AM -0400, James Bottomley wrote:
> > > On Mon, 2016-06-20 at 11:03 +0300, Jani Nikula wrote:
> > > > Cc: Ville
> > > > 
> > > > On Mon, 20 Jun 2016, James Bottomley <
> > > > James.Bottomley@HansenPartnership.com> wrote:
> > > > > OK, my candidate bad commit is this one:
> > > > > 
> > > > > commit a05628195a0d9f3173dd9aa76f482aef692e46ee
> > > > > Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > > > Date:   Mon Apr 11 10:23:51 2016 +0300
> > > > > 
> > > > >     drm/i915: Get panel_type from OpRegion panel details
> > > > > 
> > > > > After being more careful about waiting to identify flicker, 
> > > > > this one seems to be the one the bisect finds.  I'm now 
> > > > > running v4.7-rc3 with this one reverted and am currently 
> > > > > seeing no flicker problems.   It is, however, early days 
> > > > > because the flicker can hide for long periods, so I 'll wait 
> > > > > until Monday evening and a few reboots before declaring
> > > > > victory.
> > > > 
> > > > If that turns out to be the bad commit, it doesn't really 
> > > > surprise me, and that in itself is depressing.
> > > 
> > > As far as I can tell, after running for a day with this reverted,
> > > this is the problem.  The flicker hasn't appeared with it 
> > > reverted.  It's pretty noticeable with this commit included.
> > 
> > Hmm. The only difference I can see is low vs. normal vswing. Panel 
> > 0 has low, panel 2 has normal. So either the VBT or opregion is
> > telling utter lies, or there's some other bug in our low vswing
> > support.
> > 
> > To confirm it's really a vswing issue, you should be able to run 
> > with i915.edp_vswing=2 without flickers on the broken kernel.
> 
> Preliminary boot indicates no flicker with the bad commit included 
> and this option, but I'll have to run for quite a bit longer to 
> verify, since it can sometimes be elusive.

Two days of runtime seems to confirm this is the problem (still no
flicker issues).

James

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#1429795 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

[Multipart message — attachments visible in raw view] — view raw

On Sun, 2016-06-19 at 14:53 -0700, James Bottomley wrote:
> On Fri, 2016-06-17 at 16:06 -0700, James Bottomley wrote:
> > On Fri, 2016-06-17 at 16:34 +0300, Jani Nikula wrote:
> > > On Fri, 17 Jun 2016, Daniel Vetter <daniel@ffwll.ch> wrote:
> > > > On Thu, Jun 16, 2016 at 03:42:12PM -0700, James Bottomley
> > > > wrote:
> > > > > On Thu, 2016-06-16 at 14:29 -0700, James Bottomley wrote:
> > > > > > On Thu, 2016-06-16 at 23:24 +0200, Daniel Vetter wrote:
> > > > > > > I guess we'll need the bisect on this one to make
> > > > > > > progress.
> > > > > > 
> > > > > > Sigh, I was afraid that might be the next step.
> > > > > 
> > > > > OK, I have a curious data point.  I assumed the problem would
> > > > > be
> > > > > somewhere in the drm update, so I started bisecting that at
> > > > > the
> > > > > top. 
> > > > >  However, the top most commit:
> > > > > 
> > > > > commit 1d6da87a3241deb13d073c4125d19ed0e5a0c62c
> > > > > Merge: 1f40c49 a39ed68
> > > > > Author: Linus Torvalds <torvalds@linux-foundation.org>
> > > > > Date:   Mon May 23 11:48:48 2016 -0700
> > > > > 
> > > > >     Merge branch 'drm-next' of
> > > > > git://people.freedesktop.org/~airlied/linux
> > > > > 
> > > > > Isn't actually bad.  There's no flicker here, so whatever
> > > > > caused
> > > > > the
> > > > > problem came from some update after this.
> > > > 
> > > > There was a fixes pull after this. Might be worth it to
> > > > restrict
> > > > to
> > > > just
> > > > the i915 changes, which are just
> > > > 5b4fd5b1111b1230cd037..157d2c7fad0863222
> > > > 
> > > > Looking at those nothing seems to stick out which might explain
> > > > what's
> > > > happening for you.
> > 
> > OK, so just on the firmware, the system seems less flickery with
> > the
> > new 1.4.3 UEFI, so I'm starting to think it is a Skylake errata 
> > issue.  The flicker isn't gone for good, but seems to be reboot 
> > dependent (it's there in some boots, but gone on a reboot).
> > 
> > > This should be easy enough to try before bisecting:
> > > http://patchwork.freedesktop.org/patch/msgid/1466162081-12042-1-g
> > > it
> > > -s
> > > end-email-mika.kahola@intel.com
> > 
> > Applying this didn't seem to make a difference: still there on
> > some 
> > and gone on other reboots.
> 
> OK, my candidate bad commit is this one:
> 
> commit a05628195a0d9f3173dd9aa76f482aef692e46ee
> Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Date:   Mon Apr 11 10:23:51 2016 +0300
> 
>     drm/i915: Get panel_type from OpRegion panel details
> 
> After being more careful about waiting to identify flicker, this one
> seems to be the one the bisect finds.  I'm now running v4.7-rc3 with
> this one reverted and am currently seeing no flicker problems.  It
> is,
> however, early days because the flicker can hide for long periods, so
> I
> 'll wait until Monday evening and a few reboots before declaring
> victory.
> 
> 
I'm seeing this on my IvyBridge.  I'll try reverting the commit here
too, to see if it's the same issue.

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#1429796 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Thu, 23 Jun 2016, Steven Newbury <steve@snewbury.org.uk> wrote:
> [ Unknown signature status ]
> On Sun, 2016-06-19 at 14:53 -0700, James Bottomley wrote:
>> On Fri, 2016-06-17 at 16:06 -0700, James Bottomley wrote:
>> > On Fri, 2016-06-17 at 16:34 +0300, Jani Nikula wrote:
>> > > On Fri, 17 Jun 2016, Daniel Vetter <daniel@ffwll.ch> wrote:
>> > > > On Thu, Jun 16, 2016 at 03:42:12PM -0700, James Bottomley
>> > > > wrote:
>> > > > > On Thu, 2016-06-16 at 14:29 -0700, James Bottomley wrote:
>> > > > > > On Thu, 2016-06-16 at 23:24 +0200, Daniel Vetter wrote:
>> > > > > > > I guess we'll need the bisect on this one to make
>> > > > > > > progress.
>> > > > > > 
>> > > > > > Sigh, I was afraid that might be the next step.
>> > > > > 
>> > > > > OK, I have a curious data point.  I assumed the problem would
>> > > > > be
>> > > > > somewhere in the drm update, so I started bisecting that at
>> > > > > the
>> > > > > top. 
>> > > > >  However, the top most commit:
>> > > > > 
>> > > > > commit 1d6da87a3241deb13d073c4125d19ed0e5a0c62c
>> > > > > Merge: 1f40c49 a39ed68
>> > > > > Author: Linus Torvalds <torvalds@linux-foundation.org>
>> > > > > Date:   Mon May 23 11:48:48 2016 -0700
>> > > > > 
>> > > > >     Merge branch 'drm-next' of
>> > > > > git://people.freedesktop.org/~airlied/linux
>> > > > > 
>> > > > > Isn't actually bad.  There's no flicker here, so whatever
>> > > > > caused
>> > > > > the
>> > > > > problem came from some update after this.
>> > > > 
>> > > > There was a fixes pull after this. Might be worth it to
>> > > > restrict
>> > > > to
>> > > > just
>> > > > the i915 changes, which are just
>> > > > 5b4fd5b1111b1230cd037..157d2c7fad0863222
>> > > > 
>> > > > Looking at those nothing seems to stick out which might explain
>> > > > what's
>> > > > happening for you.
>> > 
>> > OK, so just on the firmware, the system seems less flickery with
>> > the
>> > new 1.4.3 UEFI, so I'm starting to think it is a Skylake errata 
>> > issue.  The flicker isn't gone for good, but seems to be reboot 
>> > dependent (it's there in some boots, but gone on a reboot).
>> > 
>> > > This should be easy enough to try before bisecting:
>> > > http://patchwork.freedesktop.org/patch/msgid/1466162081-12042-1-g
>> > > it
>> > > -s
>> > > end-email-mika.kahola@intel.com
>> > 
>> > Applying this didn't seem to make a difference: still there on
>> > some 
>> > and gone on other reboots.
>> 
>> OK, my candidate bad commit is this one:
>> 
>> commit a05628195a0d9f3173dd9aa76f482aef692e46ee
>> Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> Date:   Mon Apr 11 10:23:51 2016 +0300
>> 
>>     drm/i915: Get panel_type from OpRegion panel details
>> 
>> After being more careful about waiting to identify flicker, this one
>> seems to be the one the bisect finds.  I'm now running v4.7-rc3 with
>> this one reverted and am currently seeing no flicker problems.  It
>> is,
>> however, early days because the flicker can hide for long periods, so
>> I
>> 'll wait until Monday evening and a few reboots before declaring
>> victory.
>> 
>> 
> I'm seeing this on my IvyBridge.  I'll try reverting the commit here
> too, to see if it's the same issue.

IvyBridge doesn't have low vswing for eDP. If reverting helps, it's a
different failure mode.

BR,
Jani.

-- 
Jani Nikula, Intel Open Source Technology Center

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#1429810 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

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On Thu, 2016-06-23 at 15:59 +0300, Jani Nikula wrote:
> On Thu, 23 Jun 2016, Steven Newbury <steve@snewbury.org.uk> wrote:
> > [ Unknown signature status ]
> > On Sun, 2016-06-19 at 14:53 -0700, James Bottomley wrote:
> > > On Fri, 2016-06-17 at 16:06 -0700, James Bottomley wrote:
> > > > On Fri, 2016-06-17 at 16:34 +0300, Jani Nikula wrote:
> > > > > On Fri, 17 Jun 2016, Daniel Vetter <daniel@ffwll.ch> wrote:
> > > > > > On Thu, Jun 16, 2016 at 03:42:12PM -0700, James Bottomley
> > > > > > wrote:
> > > > > > > On Thu, 2016-06-16 at 14:29 -0700, James Bottomley wrote:
> > > > > > > > On Thu, 2016-06-16 at 23:24 +0200, Daniel Vetter wrote:
> > > > > > > > > I guess we'll need the bisect on this one to make
> > > > > > > > > progress.
> > > > > > > > 
> > > > > > > > Sigh, I was afraid that might be the next step.
> > > > > > > 
> > > > > > > OK, I have a curious data point.  I assumed the problem
> > > > > > > would
> > > > > > > be
> > > > > > > somewhere in the drm update, so I started bisecting that
> > > > > > > at
> > > > > > > the
> > > > > > > top. 
> > > > > > >  However, the top most commit:
> > > > > > > 
> > > > > > > commit 1d6da87a3241deb13d073c4125d19ed0e5a0c62c
> > > > > > > Merge: 1f40c49 a39ed68
> > > > > > > Author: Linus Torvalds <torvalds@linux-foundation.org>
> > > > > > > Date:   Mon May 23 11:48:48 2016 -0700
> > > > > > > 
> > > > > > >     Merge branch 'drm-next' of
> > > > > > > git://people.freedesktop.org/~airlied/linux
> > > > > > > 
> > > > > > > Isn't actually bad.  There's no flicker here, so whatever
> > > > > > > caused
> > > > > > > the
> > > > > > > problem came from some update after this.
> > > > > > 
> > > > > > There was a fixes pull after this. Might be worth it to
> > > > > > restrict
> > > > > > to
> > > > > > just
> > > > > > the i915 changes, which are just
> > > > > > 5b4fd5b1111b1230cd037..157d2c7fad0863222
> > > > > > 
> > > > > > Looking at those nothing seems to stick out which might
> > > > > > explain
> > > > > > what's
> > > > > > happening for you.
> > > > 
> > > > OK, so just on the firmware, the system seems less flickery
> > > > with
> > > > the
> > > > new 1.4.3 UEFI, so I'm starting to think it is a Skylake
> > > > errata 
> > > > issue.  The flicker isn't gone for good, but seems to be
> > > > reboot 
> > > > dependent (it's there in some boots, but gone on a reboot).
> > > > 
> > > > > This should be easy enough to try before bisecting:
> > > > > http://patchwork.freedesktop.org/patch/msgid/1466162081-12042
> > > > > -1-g
> > > > > it
> > > > > -s
> > > > > end-email-mika.kahola@intel.com
> > > > 
> > > > Applying this didn't seem to make a difference: still there on
> > > > some 
> > > > and gone on other reboots.
> > > 
> > > OK, my candidate bad commit is this one:
> > > 
> > > commit a05628195a0d9f3173dd9aa76f482aef692e46ee
> > > Author: Ville Syrjälä <ville.syrjala@linux.intel.com>
> > > Date:   Mon Apr 11 10:23:51 2016 +0300
> > > 
> > >     drm/i915: Get panel_type from OpRegion panel details
> > > 
> > > After being more careful about waiting to identify flicker, this
> > > one
> > > seems to be the one the bisect finds.  I'm now running v4.7-rc3
> > > with
> > > this one reverted and am currently seeing no flicker
> > > problems.  It
> > > is,
> > > however, early days because the flicker can hide for long
> > > periods, so
> > > I
> > > 'll wait until Monday evening and a few reboots before declaring
> > > victory.
> > > 
> > >  
> > I'm seeing this on my IvyBridge.  I'll try reverting the commit
> > here
> > too, to see if it's the same issue.
> 
> IvyBridge doesn't have low vswing for eDP. If reverting helps, it's a
> different failure mode.
> 
It must be something else then.  Actually, in my case linus/master is
okay.  I saw the subject and though it must be the same issue.  I'm
seeing it with drm-intel nightly/next branches.  Shall I try to bisect
it?  Symptoms are similar, although I would describe it more like
flashes of a different buffer across parts of the screen.

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#1424798 — Re: [Intel-gfx] Bad flicker on skylake HQD due to code in the 4.7 merge window

On Thu, Jun 16, 2016 at 02:29:07PM -0700, James Bottomley wrote:
> On Thu, 2016-06-16 at 23:24 +0200, Daniel Vetter wrote:
> > On Thu, Jun 16, 2016 at 11:15 PM, James Bottomley
> > <James.Bottomley@hansenpartnership.com> wrote:
> > > On Mon, 2016-06-13 at 13:14 +0300, Jani Nikula wrote:
> > > > On Tue, 31 May 2016, James Bottomley <
> > > > James.Bottomley@HansenPartnership.com> wrote:
> > > > > On Tue, 2016-05-31 at 10:51 +0300, Jani Nikula wrote:
> > > > > > On Mon, 30 May 2016, James Bottomley <
> > > > > > James.Bottomley@HansenPartnership.com> wrote:
> > > > > > > I've tested a pristine 4.6.0 system, so it's definitely
> > > > > > > something
> > > > > > > that
> > > > > > > went in during the merge window.  The flicker isn't
> > > > > > > continuous,
> > > > > > > it's
> > > > > > > periodic, with an interval of something like 2-5 seconds. 
> > > > > > >  It
> > > > > > > looks
> > > > > > > like an old analogue TV going out of sync and then
> > > > > > > resyncing.
> > > > > > >  I've
> > > > > > > attached the dmesg and X.org log below just in case they
> > > > > > > can
> > > > > > > help.
> > > > > > >  I
> > > > > > > might be able to bisect this next week, but, unfortunately,
> > > > > > > this is
> > > > > > > my
> > > > > > > current laptop and I'm travelling this week.
> > > > > > 
> > > > > > Please try i915.enable_psr=0 module parameter.
> > > > > 
> > > > > Makes no discernable difference.  Current parameter settings
> > > > > are:
> > > > 
> > > > Sorry for the silence. Would you mind trying out drm-intel
> > > > -nightly
> > > > branch of [1]?
> > > > 
> > > > BR,
> > > > Jani.
> > > > 
> > > > [1] http://cgit.freedesktop.org/drm-intel
> > > 
> > > No, flicker is still there (and in fact seems worse) with the tree
> > > with
> > > this commit at the top:
> > > 
> > > commit 3eb202ecc3668583f9ff4338211dbab47d755d1c
> > > Author: Daniel Vetter <daniel.vetter@ffwll.ch>
> > > Date:   Thu Jun 16 14:38:54 2016 +0200
> > > 
> > >     drm-intel-nightly: 2016y-06m-16d-12h-38m-37s UTC integration
> > > manifest
> > 
> > Strange indeed, I hoped the improved watermark code in -nightly would
> > help. I assume nothing in dmesg about underruns or something similar?
> 
> Not that I can tell.  I've attached the full dmesg just in case.

It is worth using drm.debug=0xe to get the full atomic modesetting
splat. There may be a tell-tale in there that we don't yet have a
warning for.
-Chris
>
-- 
Chris Wilson, Intel Open Source Technology Centre

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