| Summary: | Kernel 4.16.0+ switch amdgpu.dc=1 causes screen brightness set to 1 to be dimmed by default | ||
|---|---|---|---|
| Product: | DRI | Reporter: | Joel Sass <sass.joel> |
| Component: | DRM/AMDgpu | Assignee: | Default DRI bug account <dri-devel> |
| Status: | RESOLVED FIXED | QA Contact: | |
| Severity: | normal | ||
| Priority: | medium | CC: | harry.wentland |
| Version: | unspecified | ||
| Hardware: | x86-64 (AMD64) | ||
| OS: | Linux (All) | ||
| Whiteboard: | |||
| i915 platform: | i915 features: | ||
| Attachments: | |||
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Description
Joel Sass
2018-04-12 16:09:04 UTC
Created attachment 138804 [details]
dmesg output with amdgpu.dc=0
Created attachment 138805 [details]
Xorg.0.log with amdgpu.dc=0
Created attachment 138806 [details]
xrandr --verbose with amdgpu.dc=0
A fix I've found for the issue seems to be issueing an xrandr brightness command to each monitor output. EG: ~$ xrandr --output DP-5 --brightness .99 If brightness is set to 1, the monitor appears to lose some sort of rendering characteristic, not necessarily brightness - It's like color rendering or gamma correction change somehow. Simply changing the brightness a modicum seems to fix the issue. Created attachment 138807 [details]
xrandr --verbose with amdgpu.dc=1
Created attachment 138808 [details]
Xorg.0.log with amdgpu.dc=1
Created attachment 138809 [details]
dmesg output with amdgpu.dc=1
$ uname -a Linux nope 4.16.0+ #1 SMP Mon Apr 2 15:52:14 CEST 2018 x86_64 x86_64 x86_64 GNU/Linux ~$ lsb_release -a LSB Version: core-9.20160110ubuntu0.2-amd64:core-9.20160110ubuntu0.2-noarch:security-9.20160110ubuntu0.2-amd64:security-9.20160110ubuntu0.2-noarch Distributor ID: Ubuntu Description: Ubuntu 16.04.4 LTS Release: 16.04 Codename: xenial For DC developers: behind the scenes, brightness 1 means no-op/pass-through gamma LUT, lower brightness levels are simulated by modifying the gamma LUT accordingly. Created attachment 138814 [details] [review] [PATCH] drm/amd/display: Don't program bypass on linear regamma LUT Does this fix things for you? Okay, sadly, I wasn't clear about the kernel I was running. It's located here: https://github.com/M-Bab/linux-kernel-amdgpu and I installed the .deb created by the git contributor here: https://github.com/M-Bab/linux-kernel-amdgpu-binaries I downloaded the source listed in the first link I posted above, and it doesn't appear to have the same file structure you'd listed in your patch. I've attached amdgpu_dm_color.c to this bug. If you don't want to patch for this, I understand. I can see if I can speak to the person responsible for this repo. Created attachment 139022 [details]
I don't think this is the same file from 2.17. Sorry.
Not sure exactly how that kernel is assembled but it contains the problematic code in drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_color.c. You should be able to simply delete the block for if (__is_lut_linear(...)) in amdgpu_dm_set_regamma_lut to fix this, if the patch doesn't straight-up apply. Sorry, I completely forgot that I was using a custom kernel. I downloaded it from here: https://github.com/M-Bab/linux-kernel-amdgpu-binaries and installed the .deb files directly. Here's the source: https://github.com/M-Bab/linux-kernel-amdgpu This bug has been fixed in this branch: h https://cgit.freedesktop.org/~agd5f/linux/log/?h=drm-fixes-4.17 brightness appears as normal after building the kernel from git. Good job, and thanks. Whoops. Changing to resolved/fixed. |
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