Bug 104090 - Reduced colors on RX580 through eDP on Asus GL702ZC laptop
Summary: Reduced colors on RX580 through eDP on Asus GL702ZC laptop
Status: RESOLVED FIXED
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/AMDgpu (show other bugs)
Version: DRI git
Hardware: x86-64 (AMD64) Linux (All)
: medium normal
Assignee: Default DRI bug account
QA Contact:
URL:
Whiteboard:
Keywords: regression
Depends on:
Blocks:
 
Reported: 2017-12-04 22:39 UTC by Hein-Pieter van Braam
Modified: 2018-03-27 15:25 UTC (History)
3 users (show)

See Also:
i915 platform:
i915 features:

Attachments
Without DC: Gnome shell overview (2.19 MB, image/jpeg)
2017-12-04 22:39 UTC, Hein-Pieter van Braam 		no flags Details
DC: Gnome shell overview (1.71 MB, image/jpeg)
2017-12-04 22:40 UTC, Hein-Pieter van Braam 		no flags Details
DC: Gnome shell shutdown dialog (1.48 MB, image/jpeg)
2017-12-04 22:41 UTC, Hein-Pieter van Braam 		no flags Details
Without DC: Gnome shell shutdown dialog (1.58 MB, image/jpeg)
2017-12-04 22:41 UTC, Hein-Pieter van Braam 		no flags Details
Without DC: xrandr --prop output (1.94 KB, text/plain)
2017-12-04 22:42 UTC, Hein-Pieter van Braam 		no flags Details
Without DC: Xorg.log (40.09 KB, text/plain)
2017-12-04 22:42 UTC, Hein-Pieter van Braam 		no flags Details
Without DC: dmesg -T (94.91 KB, text/plain)
2017-12-04 22:42 UTC, Hein-Pieter van Braam 		no flags Details
DC: xrandr --prop output (1.71 KB, text/plain)
2017-12-04 22:43 UTC, Hein-Pieter van Braam 		no flags Details
DC: Xorg.log (39.39 KB, text/plain)
2017-12-04 22:43 UTC, Hein-Pieter van Braam 		no flags Details
DC: dmesg -T (95.83 KB, text/plain)
2017-12-04 22:43 UTC, Hein-Pieter van Braam 		no flags Details
Fix truncate programming (1015 bytes, patch)
2017-12-07 16:27 UTC, Harry Wentland 		no flags Details | Splinter Review
View All

Description Hein-Pieter van Braam 2017-12-04 22:39:16 UTC 
When enabling DC on the RX580 on Linux 4.15.0-rc2 I get a reduced color palette compared to having DC turned off. 

My setup: 
Fedora 27
Xorg 1.19.5
Xorg drivers amdgpu 1.3.0
Linux 4.15.0-rc2

Attached you will find dmesg, xorg, and xrandr output with and without DC along with 2 pictures with and without dc for the results that I'm talking about.
Comment 1 Hein-Pieter van Braam 2017-12-04 22:39:51 UTC 
Created attachment 135946 [details]
Without DC: Gnome shell overview
Comment 2 Hein-Pieter van Braam 2017-12-04 22:40:37 UTC 
Created attachment 135947 [details]
DC: Gnome shell overview
Comment 3 Hein-Pieter van Braam 2017-12-04 22:41:15 UTC 
Created attachment 135948 [details]
DC: Gnome shell shutdown dialog
Comment 4 Hein-Pieter van Braam 2017-12-04 22:41:41 UTC 
Created attachment 135949 [details]
Without DC: Gnome shell shutdown dialog
Comment 5 Hein-Pieter van Braam 2017-12-04 22:42:13 UTC 
Created attachment 135950 [details]
Without DC: xrandr --prop output
Comment 6 Hein-Pieter van Braam 2017-12-04 22:42:35 UTC 
Created attachment 135951 [details]
Without DC: Xorg.log
Comment 7 Hein-Pieter van Braam 2017-12-04 22:42:57 UTC 
Created attachment 135952 [details]
Without DC: dmesg -T
Comment 8 Hein-Pieter van Braam 2017-12-04 22:43:19 UTC 
Created attachment 135953 [details]
DC: xrandr --prop output
Comment 9 Hein-Pieter van Braam 2017-12-04 22:43:36 UTC 
Created attachment 135954 [details]
DC: Xorg.log
Comment 10 Hein-Pieter van Braam 2017-12-04 22:43:57 UTC 
Created attachment 135955 [details]
DC: dmesg -T
Comment 11 Michel Dänzer 2017-12-05 10:26:45 UTC 
The EDID says 6 bits per channel, maybe DC doesn't enable dithering.
Comment 12 Hein-Pieter van Braam 2017-12-06 15:22:26 UTC 
How do I establish whether that is what is happening or not? It sure looks like that's what's going on though.
Comment 13 Harry Wentland 2017-12-07 16:27:39 UTC 
Created attachment 136035 [details] [review]
Fix truncate programming

Does this help? Haven't had a chance to test it myself but this code looked obviously wrong.
Comment 14 Hein-Pieter van Braam 2017-12-07 16:40:40 UTC 
I applied attachment 136035 [details] [review] to 4.15.0-rc2 but the problem remained with dc=1 on my rx580 I'm afraid.
Comment 15 Hein-Pieter van Braam 2018-02-16 10:02:47 UTC 
I just upgraded to 4.16.0-rc1 and the problem is still there with dc=1
Comment 16 Hein-Pieter van Braam 2018-03-26 12:57:09 UTC 
It appears that 4.16.0-rc7 fixed the issue on this laptop. I'll do a bit more testing but it seems on par with a system without dc now. Great stuff.
Comment 17 Harry Wentland 2018-03-27 15:25:54 UTC 
Thanks for testing. I'll set this to resolved. If you still see issues feel free to reopen.

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