From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ben Widawsky <ben@bwidawsk.net>
Subject: Re: [PATCH 2/2] drm/i915: Don't BUG_ON in
 i915_gem_obj_offset
Date: Tue, 24 Jun 2014 18:30:34 -0700
Message-ID: <20140625013033.GA10886@bwidawsk.net>
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To: Daniel Vetter <daniel@ffwll.ch>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>, Intel Graphics Development <intel-gfx@lists.freedesktop.org>
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On Wed, Jun 18, 2014 at 12:04:46AM +0200, Daniel Vetter wrote:
> On Tue, Jun 17, 2014 at 10:34:38PM +0200, Daniel Vetter wrote:
> > A WARN_ON is perfectly fine.
> > 
> > The BUG in here seems to be the cause behind hard-hangs when I cat the
> > i915_gem_pageflip debugfs file (which calls this from an irq
> > spinlock). But only while running a full igt run after a while. I
> > still need to root cause the underlying issue.
> > 
> > I'll also start reject patches which add new BUG_ON but don't come
> > with a really good justification for it. The general rule really
> > should be to just WARN and hope the driver survives for long enough.
> > 
> > Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
> 
> Both patches merged, this one improved per Chris' suggestions on irc.
> -Daniel
> 

Hey, here's an idea. How about we root cause bugs instead of making
blanket statements about the validity of real assertions? If the callers
of ggtt_offset are calling it on unbound objects, it's a violation of
the design. And in the other cases, it's a real bug.

I'd NAK this patch if it wasn't already merged, and my NAK meant
something.

-- 
Ben Widawsky, Intel Open Source Technology Center