[PATCH v2 00/18] i.MX8MM GPC improvements and BLK_CTRL driver

[Lucas Stach]

Hi Frieder,

Am Donnerstag, dem 05.08.2021 um 20:56 +0200 schrieb Frieder Schrempf:
> On 05.08.21 12:18, Frieder Schrempf wrote:
> > On 21.07.21 22:46, Lucas Stach wrote:
> > > Hi all,
> > > 
> > > second revision of the GPC improvements and BLK_CTRL driver to make use
> > > of all the power-domains on the i.MX8MM. I'm not going to repeat the full
> > > blurb from the v1 cover letter here, but if you are not familiar with
> > > i.MX8MM power domains, it may be worth a read.
> > > 
> > > This 2nd revision fixes the DT bindings to be valid yaml, some small
> > > failure path issues and most importantly the interaction with system
> > > suspend/resume. With the previous version some of the power domains
> > > would not come up correctly after a suspend/resume cycle.
> > > 
> > > Updated testing git trees here, disclaimer still applies:
> > > https://git.pengutronix.de/cgit/lst/linux/log/?h=imx8m-power-domains
> > > https://git.pengutronix.de/cgit/lst/linux/log/?h=imx8m-power-domains-testing
> > 
> > I finally did some tests on my side using USB, GPU and DSI (no PCIe, VPU, CSI so far) and the results are promising. Thanks for the effort!
> > 
> > I will try to run some more automated suspend/resume and reboot test cycles over the weekend and report the results here afterwards.
> > 
> 
> Unfortunately I got some results sooner than I had hoped. I set up a simple loop to suspend/resume every few seconds and on the first run it took around 2-3 hours for the device to lock up on resume. On the second run it took less than half an hour. I had glmark2-es2-drm running in the background, but it looks like it crashed at some point before the lockup occurred.
> 
> Of course this could also be unrelated and caused by some peripheral driver or something but the first suspicion is definitely the power domains.
> 
> If you have any suggestions for which debug options to enable or where to add some printks, please let me know. If I do another run I would like to make sure that the resulting logs are helpful for debugging.
> 
> And I would appreciate if someone else could try to reproduce this problem on his/her side. I use this simple script for testing:
> 
> #!/bin/sh
> 
> glmark2-es2-drm &
> 
> while true;
> do
>     echo +10 > /sys/class/rtc/rtc0/wakealarm
>     echo mem > /sys/power/state
>     sleep 5
> done;

Hm, that's unfortunate.

I'm back from a two week vacation, but it looks like I won't have much
time available to look into this issue soon. It would be very helpful
if you could try to pinpoint the hang a bit more.  If you can reproduce
the hang with no_console_suspend you might be able to extract a bit
more info in which stage the hang happens (suspend, resume, TF-A, etc.)
If the hang is in the kernel you might be able to add some prints to
the suspend/resume paths to be able to track down the exact point of
the hang.

I'm happy to look into the issue once it's better known where to look,
but I fear that I won't have time to do the above investigation myself
short term. Frieder, is this something you could help with over the
next few days?

Regards,
Lucas