[Intel-gfx] "flip_done timed out" messages causing huge increase in boot time

[Daniel Kamil Kozar]

Small omission on my part : I meant 4.19.12, not 4.19.2 as the last
working version.
Also, I can confirm that reverting
13947d150bae871bd880565ada318b0bcd0e690e from the current HEAD of
linux-stable fixes the issue.

On Sat, 5 Jan 2019 at 00:47, Daniel Kamil Kozar <dkk089 at gmail.com> wrote:
>
> Hello.
> After upgrading the kernel to 4.20, I noticed that the boot time
> increased from about 5 seconds to 25 seconds. My machine is an Asus
> K53SV with an Intel i7-2630QM, i.e. Sandy Bridge. I have an external
> display connected to it via HDMI. If the display is unplugged when
> booting the machine, the boot time stays at its old value.
> The kernel log shows two messages like this :
>
> [   15.747206] [drm:drm_atomic_helper_wait_for_flip_done
> [drm_kms_helper]] *ERROR* [CRTC:39:pipe A] flip_done timed out
> [   26.198968] [drm:drm_atomic_helper_wait_for_dependencies
> [drm_kms_helper]] *ERROR* [CRTC:39:pipe A] flip_done timed out
>
> Which are the only ones that don't appear in 4.19.2, where the boot
> time was smaller. Bisecting the commits between these two versions
> leads to commit 516a49cc19467e298d08a404f73a6e311f4548d1.
>
> Let me know if you need more information.
>
> Kind regards,
> Daniel