Re: Debugging DRM on a laptop?

[Paul Goyette <paul%whooppee.com@localhost>]

On Sun, 5 Aug 2018, coypu%sdf.org@localhost wrote:

> Hi folks,
>
> we're working on a drmkms update.
> I'm testing it on a Dell XPS 9550. It's a laptop with a Skylake CPU.
> It has a power button. The power button powers off, not reboot.
> This means the dmesg buffer gets wiped.
> No serial console as far as I know.
>
> Now it reaches a point where the screen changes, but my DDB_COMMANDENTER
> containing "reboot" won't do the expected thing. It's possible it's
> hanging. I can't seem to blindly enter ddb.
>
> Any suggestions to make debugging less painful?
> Something like arm a watchdog to panic after some time.
>
> I'm gonna experiment with sprinkling panic("XXX"); and see if this works
> out.

Can't you tell DDB to 'reboot 0x100' to force a crash dump?  Then the 
message buffer should be saved in the dump file.


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| Paul Goyette     | PGP Key fingerprint:     | E-mail addresses:          |
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