Dull colors with kernel 5.2.0 on external monitors with intel-gfx
Submitted by Bernd Buschinski
Assigned to Intel GFX Bugs mailing list
Link to original bug (#111452)
Description
With kernel 5.2.0 my colors on my external monitors are kind of dull.
Meaning the contrast seems lower and the gamma seems higher.
It worked fine with kernel 5.1.0.
It can be worked around with:
xrandr --output DP-1-1 --set 'Broadcast RGB' 'Full'
xrandr --output DP-1-2 --set 'Broadcast RGB' 'Full'
Only the external monitors (connected via laptop -> docking station -> display port) are affected. The laptop display is fine.
I started bisecting it and result is:
37aa52bff2bcd4377c0f747f730f3d436f2fe58e is the first bad commit
commit 37aa52bff2bcd4377c0f747f730f3d436f2fe58e
Author: Ville Syrjälä ville.syrjala@linux.intel.com
Date: Tue Mar 26 16:25:51 2019 +0200
drm/i915: Add broadcast RGB property for DP MST
Add the "Broadcast RGB" property to MST connectors, and implement
the same logic for it as we have in the SST code.
v2: Extract and reuse intel_dp_limited_color_range()
Cc: Ivan Vlk ari@adyline.sk
Tested-by: Ivan Vlk ari@adyline.sk
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=108821
Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com
Reviewed-by: Jani Nikula jani.nikula@intel.com #v1
Link: https://patchwork.freedesktop.org/patch/msgid/20190326142556.21176-1-ville.syrjala@linux.intel.com
drivers/gpu/drm/i915/intel_dp.c | 39 ++++++++++++++++++++++++-------------
drivers/gpu/drm/i915/intel_dp_mst.c | 15 ++++++++++++--
drivers/gpu/drm/i915/intel_drv.h | 2 ++
3 files changed, 40 insertions(+), 16 deletions(-)
CPU: Intel(R) Core(TM) i5-6300U CPU @ 2.40GHz
Laptop: Dell Latitude E7470
Software:
- xorg-server-1.20.5
- mesa-19.1.3
- libdrm-2.4.99
Kernel Bugzilla Link: https://bugzilla.kernel.org/show_bug.cgi?id=204351