Ant P. Watchman
Joined: 18 Apr 2009 Posts: 6920
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Posted: Mon Feb 19, 2018 1:28 am Post subject: amdgpu in kernel 4.15: HDMI monitor stuck in YPbPr |
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I'm using an RX550, kernel 4.15.4, with the amdgpu DC kernel option enabled and amdgpu.audio=1.
After upgrading to 4.15 I've found my video card is mangling HDMI output. I have a dual-monitor arrangement and my main one (attached via DisplayPort) looks fine, but the HDMI-connected second one has visible colour sub-sampling artifacts - red text on a dark terminal looks particularly awful and shimmers when I drag the window on that screen.
I remember there used to be an xrandr property to switch the colour format between rgb/ypbpr/tv_rgb, but I just checked and it's not there any more:
Code: | ~ $ xrandr --verbose
Screen 0: minimum 320 x 200, current 5760 x 2160, maximum 16384 x 16384
DisplayPort-0 connected primary 3840x2160+0+0 (0x58) normal (normal left inverted right x axis y axis) 600mm x 340mm
Identifier: 0x54
Timestamp: 2297116
Subpixel: unknown
Gamma: 1.0:1.0:1.0
Brightness: 1.0
Clones:
CRTC: 0
CRTCs: 0 1 2 3 4
Transform: 1.000000 0.000000 0.000000
0.000000 1.000000 0.000000
0.000000 0.000000 1.000000
filter:
EDID:
00ffffffffffff001e6d095bd95f0800
[...]
000000000000000000000000000000c8
TearFree: on
supported: off, on, auto
underscan vborder: 0
range: (0, 128)
underscan hborder: 0
range: (0, 128)
underscan: off
supported: off, on, auto
scaling mode: None
supported: None, Full, Center, Full aspect
non-desktop: 0
range: (0, 1)
link-status: Good
supported: Good, Bad
3840x2160 (0x58) 533.250MHz +HSync -VSync *current +preferred
h: width 3840 start 3888 end 3920 total 4000 skew 0 clock 133.31KHz
v: height 2160 start 2214 end 2219 total 2222 clock 60.00Hz
[...]
640x480 (0x6c) 25.175MHz -HSync -VSync
h: width 640 start 656 end 752 total 800 skew 0 clock 31.47KHz
v: height 480 start 490 end 492 total 525 clock 59.94Hz
HDMI-A-0 connected 1920x1200+3840+0 (0x6d) normal (normal left inverted right x
axis y axis) 518mm x 324mm
Identifier: 0x55
Timestamp: 2297116
Subpixel: unknown
Gamma: 1.0:1.0:1.0
Brightness: 1.0
Clones:
CRTC: 1
CRTCs: 0 1 2 3 4
Transform: 1.000000 0.000000 0.000000
0.000000 1.000000 0.000000
0.000000 0.000000 1.000000
filter:
EDID:
00ffffffffffff0010ac16f04c4c3441
[...]
1800000000000000000000000000003e
TearFree: on
supported: off, on, auto
underscan vborder: 0
range: (0, 128)
underscan hborder: 0
range: (0, 128)
underscan: off
supported: off, on, auto
scaling mode: None
supported: None, Full, Center, Full aspect
non-desktop: 0
range: (0, 1)
link-status: Good
supported: Good, Bad
1920x1200 (0x6d) 154.000MHz +HSync -VSync *current +preferred
h: width 1920 start 1968 end 2000 total 2080 skew 0 clock 74.04KHz
v: height 1200 start 1203 end 1209 total 1235 clock 59.95Hz
[...]
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There's nothing odd in dmesg or Xorg.0.log; X sees the display supports RGB 4:4:4 but isn't using it. I can't see anything DRM-related in /sys/ that'd let me change it either.
I've had similar problems with the radeon driver and HDMI in the past, but this is a new one to me. |
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