[Intel-gfx] [PATCH 02/12] drm/i915: BUG_ON bad PPGTT offset

[Daniel Vetter]

On Wed, May 8, 2013 at 6:48 PM, Ben Widawsky <ben at bwidawsk.net> wrote:
>> >> Queued for -next with the same s/BUG/WARN bikeshed, thanks for the patch.
>> >> -Daniel
>> >
>> > If you're going to change to WARN, please fixup the patch to return
>> > early... if (WARN_ON(...)) return
>> >
>> > The GPU will end up hanging if we've messed this up...
>>
>> I don't care about the gpu, only that the logs hit the disc. And I
>> don't see how an early return can safe anything in here, since
>> something went horribly wrong already anyway.
>> -Daniel
>
> Seriously? Feels a bit like this has become an argument for arguments
> sake, but: I'd much rather have an assertion fail than a gpu error state
> from same random point in time later.

You still get the assertion fail in dmesg with the WARN. The
difference to a BUG is that we don't kill X, which means you can still
vt-switch and get out of the graphical console mode and restore fbcon.
For normal users that's imo much better (and the gpu crapping out
later on, well meh).
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch