Re: [PATCH 8/8] drm/i915: remove early fb allocation dependency on CONFIG_FB v2

Jesse Barnes
2014-03-09T17:32:28Z

On Sat, 8 Mar 2014 11:33:15 +0100
Daniel Vetter <daniel@ffwll.ch> wrote:

> On Fri, Mar 07, 2014 at 08:57:55AM -0800, Jesse Barnes wrote:
> > By stuffing the fb allocation into the crtc, we get mode set lifetime
> > refcounting for free, but have to handle the initial pin & fence
> > slightly differently. It also means we can move the shared fb handling
> > into the core rather than leaving it out in the fbdev code.
> >
> > v2: null out crtc->fb on error (Daniel)
> > take fbdev fb ref and remove unused error path (Daniel)
> >
> > Requested-by: Daniel Vetter <daniel@ffwll.ch>
> > Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
>
> Ok, I've merged patches 1-4 and this one here from the series. Not
> terribly happy that you didn't squash in this fixup, since now people
> might stumble over the strange lifetime rules of the previous patches. But
> meh ;-)

Yeah even though there's a handoff from the core to the fbdev side, I
still think they're correct as far as fbs go. The underlying obj ref
may not be correct though; I think that was papering over an earlier
bug.

Either way those should manifest as a leaked object (the stolen fb will
stick around forever) rather than a crash or something. Whereas this
last patch is more likely to cause serious trouble I think since it's a
bit more invasive and relies on some other bits more...

Anyway thanks, looking forward to seeing the perf data on the swizzle
stuff.

--
Jesse Barnes, Intel Open Source Technology Center