Arch Linux

Description:
- since 4.18, the hdmi output says "12 bit"
- since 4.18.8 there's no video output !!

(You can find more details in this thread https://bbs.archlinux.org/viewtopic.php?id=241212)

After two bisections I found the bad commits for both issues. I did already report the bug upstream https://bugs.freedesktop.org/show_bug.cgi?id=108542
I did also test 4.19 kernel avaible in Testing repository, and reverting those commits everything works fine again.

commit e03fd3f300f6184c1264186a4c815e93bf658abb
Author: Mikita Lipski <mikita.lipski@amd.com>
Date: Wed May 16 16:46:18 2018 -0400

drm/amd/display: Do not limit color depth to 8bpc

Delete if statement that would force any display's color depth higher
than 8 bpc to 8

Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Reviewed-by: Harry Wentland <Harry.Wentland@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

:040000 040000 57c7a743a10059addbfdd1a122f90c4053d377fa 13139317e62ef56db1748bf48f31f81eb986c7f8 M drivers

##########################

commit 691f2d763d0731224439686ecf2d440df8fe910e
Author: Mikita Lipski <mikita.lipski@amd.com>
Date: Fri Jul 13 09:07:35 2018 -0400

drm/amd/display: update clk for various HDMI color depths

commit 81aca8e75c1b046865fb2badef95a0dcff6f73de upstream.

[why]
When programming tonga's connector's backend we didn't take
in account that HDMI's colour depth might be more than 8bpc
therefore we need to add a switch statement that would adjust
the pixel clock accordingly.

[how]
Add a switch statement updating clock by its appropriate
coefficient.

Signed-off-by: Mikita Lipski <mikita.lipski@amd.com>
Reviewed-by: Charlene Liu <Charlene.Liu@amd.com>
Acked-by: Bhawanpreet Lakha <Bhawanpreet.Lakha@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

:040000 040000 ef9f989910439dc8749f1440863e3e26646d5fa1 c9ae9b8a137f9ef9d62147fcc28ea25fc4ffbc1e M drivers