Re: kabylake + drm-515-kmod/drm-510-kmod hangs

On Mon, Aug 21, 2023 at 10:44:28AM -0700, Pete Wright wrote:
> hey there,
> i've got a kabylake laptop that i've been using with drm-kmod for several
> years without much hassle.  after upgrading to a new CURRENT this weekend
> I've found that when loading either the 510 or 515 drm-kmod kernel modules
> my system will hang.
> 
> unfortunately i am not getting a panic or crash, the screen stops updating
> and i am unable to ping or SSH into the system.  interestingly the capslock
> LED still toggles but doing a CTL+ALT+DEL does not seem to do anything
> useful and i have to manually power cycle.

Does your system have the debug.debugger_on_panic sysctl set to 1?  If
so, does setting it to 0 allow the system to reboot following the hang?

> any tips for finding out what's going on?  i've booted the system with
> verbose dmesg output, and loaded the module with "kldload -v" but do not get
> any useful output.

Commit cedc82c0466a in src changed the layout of a structure used by a
stub in the GPU firmware kernel modules.  If you rebuild the one(s) you
need from ports, does the problem persist?

FWIW I had to do this:

$ cd /usr/ports/graphics/gpu-firmware-intel-kmod
$ sudo make reinstall FLAVOR=kabylake