Public bug reported:

Since kernel 4.1 laptop HP Elitebook Folio 1040 G1 (with Intel i5-4210U)
has a pretty issue with flickering

Symptoms:
1) If I leave mouse cursor for a few seconds, then start moving it, there's 
slight flicker (like display brightness changes a bit)
2) On the top left corner sometimes appears artifacts. It's relatively easy to 
see with black window decorations on top of the screen. This one is showed at 
the attached video bellow
3) With kernel boot options
drm.debug=0x1e log_buf_len=4M

dmesg shows constant refresh rate changes (even if it's set to 40HZ)
[   29.977378] [drm:intel_dp_set_drrs_state [i915]] eDP Refresh Rate set to : 
40Hz
[   30.456537] [drm:intel_dp_set_drrs_state [i915]] eDP Refresh Rate set to : 
60Hz
[   33.973392] [drm:intel_dp_set_drrs_state [i915]] eDP Refresh Rate set to : 
40Hz
[   35.055923] [drm:intel_dp_set_drrs_state [i915]] eDP Refresh Rate set to : 
60Hz

nomodeset boot option eliminates flickering

Turns out Display Refresh Rate Switching (DRRS) feature doesn't work
correctly here. It was implemented on kernels 4.0...4.1 but on a
particular machine flickering started with 4.1.

As a workaround I'm attaching a patch which disables DRRS by default and
adds module parameter "enable_drrs" to activate it. It's made for kernel
5.12 and should work for older versions as well (tested with 5.11).

Until this issue is resolved, please consider adding parameter to
disable DRRS. Windows has such option on Intel® Graphics Command Center.

** Affects: linux
     Importance: Unknown
         Status: Unknown

** Affects: linux (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: 1040 flickering folio g1 hp i915

** Patch added: "Patch to disable DRRS by default with parameter to enable it"
   
https://bugs.launchpad.net/bugs/1928138/+attachment/5496449/+files/disable_drrs_by_default_5-12.patch

** Bug watch added: gitlab.freedesktop.org/drm/intel/-/issues #3441
   https://gitlab.freedesktop.org/drm/intel/-/issues/3441

** Also affects: linux via
   https://gitlab.freedesktop.org/drm/intel/-/issues/3441
   Importance: Unknown
       Status: Unknown

** Description changed:

  Since kernel 4.1 laptop HP Elitebook Folio 1040 G1 (with Intel i5-4210U)
  has a pretty issue with flickering
  
  Symptoms:
  1) If I leave mouse cursor for a few seconds, then start moving it, there's 
slight flicker (like display brightness changes a bit)
  2) On the top left corner sometimes appears artifacts. It's relatively easy 
to see with black window decorations on top of the screen. This one is showed 
at the attached video bellow
  3) With kernel boot options
  drm.debug=0x1e log_buf_len=4M
+ 
  dmesg shows constant refresh rate changes (even if it's set to 40HZ)
  [   29.977378] [drm:intel_dp_set_drrs_state [i915]] eDP Refresh Rate set to : 
40Hz
  [   30.456537] [drm:intel_dp_set_drrs_state [i915]] eDP Refresh Rate set to : 
60Hz
  [   33.973392] [drm:intel_dp_set_drrs_state [i915]] eDP Refresh Rate set to : 
40Hz
  [   35.055923] [drm:intel_dp_set_drrs_state [i915]] eDP Refresh Rate set to : 
60Hz
  
  nomodeset boot option eliminates flickering
  
  Turns out Display Refresh Rate Switching (DRRS) feature doesn't work
  correctly here. It was implemented on kernels 4.0...4.1 but on a
  particular machine flickering started with 4.1.
  
  As a workaround I'm attaching a patch which disables DRRS by default and
  adds module parameter "enable_drrs" to activate it. It's made for kernel
  5.12 and should work for older versions as well (tested with 5.11).
  
  Until this issue is resolved, please consider adding parameter to
  disable DRRS. Windows has such option on Intel® Graphics Command Center.

-- 
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https://bugs.launchpad.net/bugs/1928138

Title:
  Flickering on built-in display (Intel Haswell graphics) since kernel
  v4.1  [bissected and workaround attached]

Status in Linux:
  Unknown
Status in linux package in Ubuntu:
  New

Bug description:
  Since kernel 4.1 laptop HP Elitebook Folio 1040 G1 (with Intel
  i5-4210U) has a pretty issue with flickering

  Symptoms:
  1) If I leave mouse cursor for a few seconds, then start moving it, there's 
slight flicker (like display brightness changes a bit)
  2) On the top left corner sometimes appears artifacts. It's relatively easy 
to see with black window decorations on top of the screen. This one is showed 
at the attached video bellow
  3) With kernel boot options
  drm.debug=0x1e log_buf_len=4M

  dmesg shows constant refresh rate changes (even if it's set to 40HZ)
  [   29.977378] [drm:intel_dp_set_drrs_state [i915]] eDP Refresh Rate set to : 
40Hz
  [   30.456537] [drm:intel_dp_set_drrs_state [i915]] eDP Refresh Rate set to : 
60Hz
  [   33.973392] [drm:intel_dp_set_drrs_state [i915]] eDP Refresh Rate set to : 
40Hz
  [   35.055923] [drm:intel_dp_set_drrs_state [i915]] eDP Refresh Rate set to : 
60Hz

  nomodeset boot option eliminates flickering

  Turns out Display Refresh Rate Switching (DRRS) feature doesn't work
  correctly here. It was implemented on kernels 4.0...4.1 but on a
  particular machine flickering started with 4.1.

  As a workaround I'm attaching a patch which disables DRRS by default
  and adds module parameter "enable_drrs" to activate it. It's made for
  kernel 5.12 and should work for older versions as well (tested with
  5.11).

  Until this issue is resolved, please consider adding parameter to
  disable DRRS. Windows has such option on Intel® Graphics Command
  Center.

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