Bug 89002 - [BSW] testdisplay shows black screen for 4K monitor
Summary: [BSW] testdisplay shows black screen for 4K monitor
Status: CLOSED FIXED
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: unspecified
Hardware: Other All
: high critical
Assignee: Ville Syrjala
QA Contact: Intel GFX Bugs mailing list
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2015-02-06 06:03 UTC by Jeff Zheng
Modified: 2016-10-05 05:28 UTC (History)
1 user (show)

See Also:
i915 platform:
i915 features:

Attachments
dmesg with 4K monitor (483.41 KB, text/plain)
2015-02-06 06:03 UTC, Jeff Zheng 		no flags Details
View All

Description Jeff Zheng 2015-02-06 06:03:51 UTC 
Created attachment 113217 [details]
dmesg with 4K monitor

==System Environment==
--------------------------
BIOS: V55 with 'dynamic memory self refresh' disabled

Regression: No. First test on 4K monitor

Non-working platforms: BSW

==kernel==
--------------------------
-testing: 2015_01_30 commit 4d3645e40c7039f60b6db0ce9c2251ac34faef81 (fails)

==Bug detailed description==
-----------------------------
Running "testdisplay -a", HDMI screen is black on following modes 
CRTC(30):[0]  3840x2160 30 3840 4016 4104 4400 2160 2168 2178 2250 0x5 0x48 297000
CRTC(30):[1]  3840x2160 30 3840 4016 4104 4400 2160 2168 2178 2250 0x5 0x40 296704
CRTC(30):[2]  3840x2160 25 3840 4896 4984 5280 2160 2168 2178 2250 0x5 0x40 297000
CRTC(30):[3]  3840x2160 24 3840 5116 5204 5500 2160 2168 2178 2250 0x5 0x40 297000
CRTC(30):[4]  3840x2160 24 3840 5116 5204 5500 2160 2168 2178 2250 0x5 0x40 296704
CRTC(30):[5]  1920x1200 60 1920 1968 2000 2080 1200 1203 1209 1235 0x9 0x40 154000
CRTC(30):[6]  1920x1080 60 1920 2008 2052 2200 1080 1082 1087 1125 0x5 0x40 148500
CRTC(30):[7]  1920x1080 60 1920 2008 2052 2200 1080 1084 1089 1125 0x5 0x40 148500
CRTC(30):[8]  1920x1080 60 1920 2008 2052 2200 1080 1084 1089 1125 0x5 0x40 148352
...

==Reproduce steps==
---------------------------- 
1. Run "testdisplay -a"
2. Check output of DP
Comment 1 Jani Nikula 2015-02-10 12:47:47 UTC 
[    4.836820] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU pipe C FIFO underrun

Ville, can we do 4k on bsw hdmi?
Comment 2 Ville Syrjala 2015-02-10 12:59:11 UTC 
(In reply to Jani Nikula from comment #1)
> [    4.836820] [drm:intel_cpu_fifo_underrun_irq_handler [i915]] *ERROR* CPU
> pipe C FIFO underrun
> 
> Ville, can we do 4k on bsw hdmi?

Not before we get the cdclk code fixed. These systems boot with cdclk @ 266MHz which is too low. We need to increase it to 320MHz when driving 4k modes. Patches are in some kind of review limbo, and there's another patch (reduce cdclk guardband to 5% from 10%) I've not yet posted that is also needed for HDMI 4k.
Comment 3 Jeff Zheng 2015-03-06 10:59:09 UTC 
Tried on drm-intel-testing-2015-02-27 + "attachment 113995 [details] [review]" and this issue still exists.

Whatever connect 4K monitor with DP/HDMI, the monitor screen is black after boot.

The differenece is that "testdisplay -a" might work sometimes on DP port, meanwhile "testdisplay -a" on HDMI port is always black screen.
Comment 4 Jeff Zheng 2015-03-20 03:12:48 UTC 
Tried drm-intel-testing-2015-03-13 on V59 BIOS and upgraded processor, this issue is fixed.
Comment 5 Jari Tahvanainen 2016-10-05 05:28:46 UTC 
Closing verified+fixed.

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