Bug 94866

Summary: [BXT-P/APL][Regression]HDMI monitor display nothing under 4K resolution
Product: DRI Reporter: Lu, Han <han.lu>
Component: DRM/IntelAssignee: Intel GFX Bugs mailing list <intel-gfx-bugs>
Status: CLOSED FIXED QA Contact: Intel GFX Bugs mailing list <intel-gfx-bugs>
Severity: blocker    
Priority: highest CC: han.lu, intel-gfx-bugs
Version: unspecified   
Hardware: x86-64 (AMD64)   
OS: Linux (All)   
Whiteboard:
i915 platform: BXT i915 features: display/HDMI
Attachments:
Description Flags
dmesg none

Description Lu, Han 2016-04-08 03:10:25 UTC 
System Environment
Platform: Apollo lake RVP1a FabA
BIOS: APLKRVPA.X64.0125.B30.1602180044
KSC FW:1.10
BXT SOC : B0
GOP : 10.0.1025
Board ID: APL RVP 1A (01)
CPU Flavor: BXT Tablet (0)
FAB ID: FAB1
Total Memory : 8GB
Kernel:4.6.0-rc1
Tree: git://anongit.freedesktop.org/drm-intel
Branch:drm-intel-nightly
Commit: 2702045fbd4188c1c26bd890bc43976fd10937ad
HW-rework: F-28C, F-27

Bug detailed description
HDMI monitor display nothing under 4K resolution.

Reproduce Steps
1.$ xinit &
2.$ xrandr --output HDMI2 --mode 3840x2160

Expected Result
HDMI monitor display normal under 4K resolution.

Actual Result
display nothing.
Comment 1 Lu, Han 2016-04-08 03:14:43 UTC 
The issue is reproduced on APL B0 with F-28C and F-27 rework, not reproduced on A0.
Comment 2 Lu, Han 2016-04-08 08:51:24 UTC 
Created attachment 122815 [details]
dmesg

Keqiao captured the dmesg with drm.debug=14
Comment 3 Imre Deak 2016-04-08 09:21:34 UTC 
Does it work with a lower resolution for the HDMI output?

Can you provide the log for the successful modeset with the same display outputs on the A0?

Please try if the following patch helps:
https://lists.freedesktop.org/archives/intel-gfx/2016-March/090016.html
Comment 4 Lu, Han 2016-04-11 03:10:26 UTC 
The issue does not exists with lower resolutions on HDMI output.
Good news is, with the patch on your link, the issue is not reproduced on B0. Is the patch on processing of upstream?
Comment 5 Imre Deak 2016-04-11 09:54:18 UTC 
(In reply to Lu, Han from comment #4)
> The issue does not exists with lower resolutions on HDMI output.
> Good news is, with the patch on your link, the issue is not reproduced on
> B0. Is the patch on processing of upstream?

Ok, thanks for testing it. Yes I'm going to merge the patch.
Comment 6 Imre Deak 2016-04-11 11:13:20 UTC 
Fix merged to drm-intel-nightly.

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