Created attachment 144072 [details]
NUC with UHD color enabled at 1080p then I switch resolution to 4k
For some reason on Gemini Lake NUC - NUC7CJYH
Latest DRM-tip kernel - latest firmware in Samsung QLED 2018
There is no signal if "HDMI UHD color" is enabled for HDMI where is NUC connected
Here log where is HDMI UHD Color enabled (no signal on TV)
Here where HDMI UHD Color is Disable (no problem)
I Discover its working when is UHD color Enabled and 1080p resolution
but when you switch to 4k signal gone :(
I Attached log where I boot NUC with UHD color enabled at 1080p then I switch resolution to 4k and signal gone
Please attach logs/etc. directly to the bug. Otherwise they may be lost and then the bug report is useless.
@Ram, any comments here?
Based on the observations shared, for me it looks like an issue with deep color at 4k. Ville might have insight into this issue.
@shashank for analyzing the issue. Adding him for the comment here.
Created attachment 144106 [details] [review]
4k@60 enabling hacks
Created attachment 144107 [details] [review]
4k@60 enabling hacks
I was working with Piotr in a parallel thread, and I could root cause the problem while handling deep color stuff.
- When we allow the CMDB modes to be treated as 4:2:0 modes (rather than RGB) && - we don't allow the deep color output (12 BPC)
we could see both 4k@30 and 4k@60 displays.
I will add some more findings here. Meanwhile, adding patches which we used to enable 4k@60.
there are any news ? or something what we can test it ?
There are 2 new patches merged in drm-tip with which we are able to see 4k@60 outputs on both GLK and ICL. Can we please confirm this observation ?
Created attachment 144399 [details]
Created attachment 144400 [details]
ok I tested latest drm-tim from today and nothing was fixed :(
yes 4k@50 or 60 working but with disabled HDR (what samsung calling UHD colors)
I attached for other 2 EDID (sorry by mistake thay had opposite name enabled actual I disabled etc.)
and I will attach 2 logs - one with enabled and one with disabled HDR support on TV
Created attachment 144401 [details]
Created attachment 144402 [details]
from the logs, I can see:
extended colorimetry: xvYCC 601
Can you please set the following property and try again:
- output colorspace: BT2020_RGB
Any news on this (or patches I can try)? I'm having exactly the same issue with my Asrock J4105 Gemini Lake ITX board and Samsung UE40NU7100 TV.
Piotr, Have you tried Shashank's proposal?
I tried to switch the colorspace to BT2020_RGB using "proptest -M i915 -D /dev/dri/card0 127 connector 131 9". This did not make any difference, still no signal.
The other thing I noticed is that when Samsung's "HDMI UHD Color" is enabled - I get "no signal" before the OS is booted, e.g. I cannot see the UEFI setup interface.
However, within the OS I get a signal with any video mode except 4K modes (even 3820x2160 @24Hz does not work).
I did more testing and this seem to be an issue with 12 BPC mode @4k resolutions. If I set the "max bpc" with proptest to 8-bit - I get a signal. No signal with any 12-bit 4k modes (including 24hz).
I want to test with 10-bit instead of 12 but I have no idea how enable the 10 bpc mode. If I limit max bpc with proptest to 10-bit - I get max 8-bit.
I can see in intel_hdmi_deep_color_possible() that we are allowing 10bpc only for GEN11(ICL) onwards.
if (bpc == 10 && INTEL_GEN(dev_priv) < 11)
This means we can't (legally) check 10bpc on GLK.
I am suspecting that this Samsung monitor is expecting something different in it's UHD deep color mode, coz I am not able to reproduce this issue with any of the UHD/HDR monitors available with me (LG, Philips). Unfortunately, this issue can't be worked upon without this particular monitor.
I removed the GEN11 restriction for 10-bit and I can confirm that it doesn't work - no signal with anything above 1080p/24.
Actually the check is there because the HW can't support this before ICL, so it is expected.
I did some more testing and I was wrong about 12-bit color. The issue is not limited to 12-bit modes. RGB 8-bit 4k @60Hz does not work either.
Looks like the issue has something to do with the HDMI link speed. All modes that require the link speed of > 9.0Gbps don't work.
Is it possible to force the driver to use YCbCr 422 12-bit instead of RGB 8-bit for 24-30Hz 4K modes? This should give a better quality/less color banding when watching videos encoded in 10-bit.