<html>
    <head>
      <base href="https://bugs.freedesktop.org/">
    </head>
    <body><table border="1" cellspacing="0" cellpadding="8">
        <tr>
          <th>Bug ID</th>
          <td><a class="bz_bug_link 
          bz_status_NEW "
   title="NEW - kernel 4.6 regression: PSR on Haswell causes screen to flash"
   href="https://bugs.freedesktop.org/show_bug.cgi?id=96704">96704</a>
          </td>
        </tr>

        <tr>
          <th>Summary</th>
          <td>kernel 4.6 regression: PSR on Haswell causes screen to flash
          </td>
        </tr>

        <tr>
          <th>Product</th>
          <td>Mesa
          </td>
        </tr>

        <tr>
          <th>Version</th>
          <td>unspecified
          </td>
        </tr>

        <tr>
          <th>Hardware</th>
          <td>x86-64 (AMD64)
          </td>
        </tr>

        <tr>
          <th>OS</th>
          <td>Linux (All)
          </td>
        </tr>

        <tr>
          <th>Status</th>
          <td>NEW
          </td>
        </tr>

        <tr>
          <th>Severity</th>
          <td>major
          </td>
        </tr>

        <tr>
          <th>Priority</th>
          <td>medium
          </td>
        </tr>

        <tr>
          <th>Component</th>
          <td>Drivers/DRI/i965
          </td>
        </tr>

        <tr>
          <th>Assignee</th>
          <td>idr@freedesktop.org
          </td>
        </tr>

        <tr>
          <th>Reporter</th>
          <td>l.jirkovsky@gmail.com
          </td>
        </tr>

        <tr>
          <th>QA Contact</th>
          <td>intel-3d-bugs@lists.freedesktop.org
          </td>
        </tr></table>
      <p>
        <div>
        <pre>Created <span class=""><a href="attachment.cgi?id=124749" name="attach_124749" title="/proc/cpuinfo">attachment 124749</a> <a href="attachment.cgi?id=124749&action=edit" title="/proc/cpuinfo">[details]</a></span>
/proc/cpuinfo

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

: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.</pre>
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