Re: [PATCH 01/11] drm: add plane support

[Daniel Vetter <daniel@ffwll.ch>]

On Tue, Oct 25, 2011 at 11:46:56AM +0200, Jesse Barnes wrote:
> Planes are a bit like half-CRTCs.  They have a location and fb, but
> don't drive outputs directly.  Add support for handling them to the core
> KMS code.
> 
> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

As discussed with Jesse on irc, drm fb handling is fragile. Current rules:
- fbs are not reference counted, hence when destroying we need to disable
  all crtcs (and now also planes) that use them. drm_framebuffer_cleanup
  does that atm
- drivers that hold onto fbs after the kms core drops the corresponding
  pointer needs to hold a ref onto the underlying backing storage (like
  e.g. for pageflip on the to-be-flipped-out fb as long as it might still
  be scanned out).

We need proper refcounting for these ... But for now this patch is missing
the plane cleanup in drm_framebuffer_cleanup.

Otherwise I think going with just the src and dst rect for set_plane is
about the only sensible thing given the crazy hw out there. But I lack the
knowledge about that kind of hw (and video stuff in general), so I'll
refrain from slapping my r-b on these two.

Cheers, Daniel
-- 
Daniel Vetter
Mail: daniel@ffwll.ch
Mobile: +41 (0)79 365 57 48