Bug 108266 - Screen flashing and dmesg flooded with *ERROR* [CONNECTOR:65:eDP-1] Link Training failed at link rate = 270000, lane count = 2 when psr enabled
Summary: Screen flashing and dmesg flooded with *ERROR* [CONNECTOR:65:eDP-1] Link Trai...
Status: NEW
Alias: None
Product: DRI
Classification: Unclassified
Component: DRM/Intel (show other bugs)
Version: unspecified
Hardware: x86-64 (AMD64) Linux (All)
: low enhancement
Assignee: Intel GFX Bugs mailing list
QA Contact: Intel GFX Bugs mailing list
URL:
Whiteboard: Triaged, ReadyForDev
Keywords:
Depends on:
Blocks:
 
Reported: 2018-10-07 16:21 UTC by kitestramuort
Modified: 2018-10-16 19:31 UTC (History)
3 users (show)

See Also:
i915 platform: BDW
i915 features: display/backlight, display/eDP, display/PSR, power/runtime PM, power/suspend-resume


Attachments
dmesg output (503.45 KB, text/x-log)
2018-10-07 16:21 UTC, kitestramuort
no flags Details
dmesg log (656.90 KB, text/x-log)
2018-10-07 18:51 UTC, kitestramuort
no flags Details
screen edid (826 bytes, text/plain)
2018-10-08 19:54 UTC, kitestramuort
no flags Details
psr-status (169 bytes, text/plain)
2018-10-08 19:54 UTC, kitestramuort
no flags Details
dmesg log (drm-tip + patches) (877.21 KB, text/x-log)
2018-10-09 20:55 UTC, kitestramuort
no flags Details
log of screen locking after blanking (1.28 MB, text/x-log)
2018-10-09 21:31 UTC, kitestramuort
no flags Details

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Description kitestramuort 2018-10-07 16:21:45 UTC
Created attachment 141929 [details]
dmesg output

If I enable psr with i915.enable_psr=1 the syslog is flooded by the message below and the screen blanks intermittently for a second or so.
 
*ERROR* [CONNECTOR:65:eDP-1] Link Training failed at link rate = 270000, lane count = 2

No such message is logged when psr is disabled and no flashing occurs.

This is on a Thinkpad T450s, Core i5-5300U, kernel 4.19.0-rc6, Arch Linux.
Comment 1 kitestramuort 2018-10-07 18:51:49 UTC
Created attachment 141930 [details]
dmesg log
Comment 2 Dhinakaran Pandiyan 2018-10-08 18:02:00 UTC
PSR on BDW isn't supported currently.

But, here's something you can try on top of drm-tip (https://cgit.freedesktop.org/drm-tip) https://patchwork.freedesktop.org/series/50654/


As documentation for future BDW enablement, it'd be great if you also attach the output of 
edid-decode /sys/class/drm/card0-eDP-1/edid and /sys/kernel/debug/dri/0/i915_edp_psr_status

-DK
Comment 3 kitestramuort 2018-10-08 19:54:07 UTC
Created attachment 141941 [details]
screen edid
Comment 4 kitestramuort 2018-10-08 19:54:32 UTC
Created attachment 141942 [details]
psr-status
Comment 5 kitestramuort 2018-10-09 07:52:51 UTC
With drm-tip and your patches the errors are gone, but the flashing still occurs albeit very occasionally. I guess PSR is still inactive on Broadwell though. 

Do you know if this platform is supposed to reach PC10? All I could get to is PC7, maybe due to lack of PSR support?
Comment 6 Jose Roberto de Souza 2018-10-09 17:28:44 UTC
Hi
Could you attach dmesg logs when running with the drm-tip & patches? Please don't forget to increase the log level(drm.debug=0x1e).

Thanks
Comment 7 kitestramuort 2018-10-09 20:55:59 UTC
Created attachment 141964 [details]
dmesg log (drm-tip + patches)
Comment 8 Jose Roberto de Souza 2018-10-09 21:05:10 UTC
There is a lot of short pulses from your eDP but no PSR or other errors detected.
Before you dump this log did you got any flashing?
Comment 9 kitestramuort 2018-10-09 21:14:54 UTC
no flashing before this dump. There is some flashing after the first time the display comes back from blanking for inactivity.  I'll try and capture a new dmesg when flashing occurs
Comment 10 kitestramuort 2018-10-09 21:30:04 UTC
So, this time the screen didn't come back from blanking. I had to force reboot. journalctl -b -1 attached. There's an *ERROR* [CRTC:39:pipe A] flip_done timed out
Comment 11 kitestramuort 2018-10-09 21:31:00 UTC
Created attachment 141965 [details]
log of screen locking after blanking
Comment 12 Jose Roberto de Souza 2018-10-16 18:01:58 UTC
The problem is '*ERROR* [CRTC:39:pipe A] flip_done timed out' but there is no clue of what caused that in your logs.

Try to reproduce with this kernel parameters: drm.debug=0x1e log_buf_len=4M
Comment 13 Jose Roberto de Souza 2018-10-16 19:31:16 UTC
Hum this may not be 100% related to PSR and there is reports of flip_done timeout with PSR disabled too in BDW:

https://bugs.freedesktop.org/show_bug.cgi?id=107732


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