[Bug 107966] Graphical corruption with PSR - affects Plymouth only

[bugzilla-daemon at freedesktop.org]

https://bugs.freedesktop.org/show_bug.cgi?id=107966

--- Comment #18 from Dhinakaran Pandiyan <dhinakaran.pandiyan at intel.com> ---
(In reply to Tom Seewald from comment #17)
> Potential workaround found:
> 
> Setting the kernel parameter i915.fastboot=1 (with i915.enable_psr=1)
> results in no screen corruption in plymouth's LUKS prompt.  This appears to
> be effective on both drm-tip and Fedora 29's 4.20.x kernel.  This issue was
> reproducible on every boot, and so far I cannot reproduce the screen
> corruption with fastboot enabled after 10+ boot cycles.
> 
> Any idea why fastboot has an effect on this?  I know that fastboot is likely
> to be set by default on SKL+ in the next kernel release, but it's still a
> bit strange that there's some interaction between psr and fastboot being
> disabled.
BIOS disables PSR, my guess is that fastboot inherits that state. A quick way
to verify would be to check i915_edp_psr_status or dmesg with drm.debug=14 at
Plymouth's login. And compare this to a boot without i915.fastboot=1. Can you
please attach dmesg for the both test cases?

Btw, you shouldn't be needing i915.enable_psr=1 on drm-tip. PSR should be
enabled by default on a KBL refresh.

-- 
You are receiving this mail because:
You are the QA Contact for the bug.
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <https://lists.freedesktop.org/archives/intel-gfx-bugs/attachments/20190201/2afa69d2/attachment-0001.html>