Bug 96704 - kernel 4.6 regression: PSR on Haswell causes screen to flash
Summary: kernel 4.6 regression: PSR on Haswell causes screen to flash
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: medium major
Assignee: Intel GFX Bugs mailing list
QA Contact: Intel GFX Bugs mailing list
Keywords: bisected, regression
Depends on:
Reported: 2016-06-28 07:46 UTC by Lukas Jirkovsky
Modified: 2016-12-15 07:54 UTC (History)
4 users (show)

See Also:
i915 platform: HSW
i915 features: display/PSR

/proc/cpuinfo (3.96 KB, text/plain)
2016-06-28 07:46 UTC, Lukas Jirkovsky
no flags Details
dmesg with drm.debug=0xe (51.44 KB, text/plain)
2016-06-28 07:46 UTC, Lukas Jirkovsky
no flags Details
/sys/kernel/debug/dri/0/i915_edp_psr_status (200 bytes, text/plain)
2016-06-28 07:47 UTC, Lukas Jirkovsky
no flags Details
lspci -vv (22.77 KB, text/plain)
2016-06-28 07:47 UTC, Lukas Jirkovsky
no flags Details
smbios-sys-info (333 bytes, text/plain)
2016-06-28 07:48 UTC, Lukas Jirkovsky
no flags Details
more verbose dmesg with drm.debug=0xe (249.85 KB, text/plain)
2016-06-29 06:40 UTC, Lukas Jirkovsky
no flags Details

Description Lukas Jirkovsky 2016-06-28 07:46:00 UTC
Created attachment 124749 [details]

After update to linux kernel 4.6 the screen started to flash. The bug may be related to #95176. Running git bisect resulted in this:

9b58e352b463f2f096d699d47b1c4c57879b617f is the first bad commit
commit 9b58e352b463f2f096d699d47b1c4c57879b617f
Author: Rodrigo Vivi <rodrigo.vivi@intel.com>
Date:   Fri Feb 12 04:08:13 2016 -0800

    drm/i915: Enable PSR by default on Haswell and Broadwell.

    With a reliable frontbuffer tracking and all instability corner cases
    on Haswell and Broadwell solved let's re-enabled PSR by default on
    these platforms.

    In case a new issue is found and PSR is the main suspect, please check
    if i915.enable_psr=0 really makes your problem go away. If this is the case
    PSR is the culprit so after that please check if i915.enable_psr=2
    or i915.enable_psr=3 solves your issue and please let us know.
    There are many panels out there and not all implementations apparently
    work as we would expect.

    In case you needed to force it on standby or disabled or in case of any
    PSR related bug please report it at bugs.freedesktop.org.
    In a bugzilla entry for PSR is desirable:
    - dmesg (drm.debug=0xe)
    - output of /sys/kernel/debug/dri/0/i915_edp_psr_status
    - Platform information. Vendor, model, id, pci id.
    - Graphical environment: Gnome, KDE, openbox, etc...
    - Details how to reproduce.
    - Also good if you could run PSR test cases of Intel-gpu-tools
    - Please mention if forcing main link standby or main link off helps you.

    There are Intel-gpu-tools test cases that can be helpful to
    determine if PSR is working as expected:
    kms_psr_sink_crc and kms_psr_frontbuffer_tracking.

    Cc: Paulo Zanoni <paulo.r.zanoni@intel.com>
    Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
    Link: http://patchwork.freedesktop.org/patch/msgid/1455278893-1307-2-git-send-email-rodrigo.vivi@intel.com
    Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
    Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

:040000 040000 9342f20d5512ade0386b728cbdeca37a66c0a17d b0776dca9c6d3d953789f7abc4a676826e373e05 M	drivers

Additional Information
The system is Lenovo Thinkpad E540. Kernel option i915.enable_psr=0 makes the problem go away. i915.enable_psr=2 or i915.enable_psr=3 does not help. Additional system information are attached.

Steps To Reproduce
Just start the system. I'm using KDE, but the screen flahsing can be seen even in console before KDE starts.
Comment 1 Lukas Jirkovsky 2016-06-28 07:46:51 UTC
Created attachment 124750 [details]
dmesg with drm.debug=0xe
Comment 2 Lukas Jirkovsky 2016-06-28 07:47:21 UTC
Created attachment 124751 [details]
Comment 3 Lukas Jirkovsky 2016-06-28 07:47:47 UTC
Created attachment 124752 [details]
lspci -vv
Comment 4 Lukas Jirkovsky 2016-06-28 07:48:16 UTC
Created attachment 124753 [details]
Comment 5 Lukas Jirkovsky 2016-06-29 06:40:12 UTC
Created attachment 124775 [details]
more verbose dmesg with drm.debug=0xe
Comment 6 yann 2016-12-14 08:19:55 UTC
Lukas, the following submitted patch https://patchwork.freedesktop.org/patch/127188/ is going to set psr by default because it's known to cause bugs -until we get proper fix. As a general rule, we really don't recommend setting any i915 options to enable or disable features.
Comment 7 Paulo Zanoni 2016-12-14 20:30:00 UTC
We just merged a patch to disable PSR by default:

commit 2ee7dc497e348eecbb82adbb1ea9e9a7e29fe921
    drm/i915: disable PSR by default on HSW/BDW

This commit is marked for inclusion in the stable Kernels, so it should reach your Linux distribution at some point soon.

Thank you for your bug report. In case you think the problem still happens, please feel free to reopen the bug.

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