[RFC][PATCH v2 0/2] drm/panic: Add a drm panic handler

[Jocelyn Falempe]

On 16/09/2023 15:09, nerdopolis wrote:
> On Friday, September 15, 2023 4:28:20 AM EDT Jocelyn Falempe wrote:
>> This introduces a new drm panic handler, which displays a message when a panic occurs.
>> So when fbcon is disabled, you can still see a kernel panic.
>>
>> This is one of the missing feature, when disabling VT/fbcon in the kernel:
>> https://www.reddit.com/r/linux/comments/10eccv9/config_vtn_in_2023/
>> Fbcon can be replaced by a userspace kms console, but the panic screen must be done in the kernel.
>>
>> This is a proof of concept, and works only with simpledrm, using a new get_scanout_buffer() api
>>
>> To test it, make sure you're using the simpledrm driver, and trigger a panic:
>> echo c > /proc/sysrq-trigger
>>
> This seems to work pretty good! With this one, I don't need to have Weston (or another display server) running for it to work this time.
> The panic reason works, which is pretty sweet.

Thanks for testing, that's really appreciated.
> 
> FYI: I do get a hunk that fails to apply in simpledrm_remove in drivers/gpu/drm/tiny/simpledrm.c
> Seems to be a change in a recentish commit
> https://github.com/torvalds/linux/commit/84e6da7ad5537826343636b846530ec2167d4a19

Thanks for the head-up, when doing this RFC, I'm based on latest 
released version v6.5, to avoid having to rebase too often.
When it's closer to merging, I will rebase to drm-misc-next.

Best regards,

-- 

Jocelyn