How to handle planes/fbs when disabling the crtc? (was Re: [Intel-gfx] [PATCH] drm/i915: use the correct obj when preparing the sprite plane)

[Daniel Vetter]

On Mon, Nov 10, 2014 at 07:15:04PM +0200, Ville Syrjälä wrote:
> As a side note if someone is looking for stuff to do, then the pin/unpin
> logic might be good thing to look at. We're currently a bit inconsistent
> whether we have the buffer pinned when the plane is disabled, or just
> otherwise invisible, or when the crtc itself is disabled. And I guess
> cooking up some tests to poke at planes with disabled crtcs might be in
> order too, as well as all kinds of variations on the
> crtc_enable->plane_enable->crtc_disable->plane_disable theme.

Hm, I've thought that thus far we've kept the buffer pinned when the crtc
is enabled (irrespective or crtc state). And when the crtc gets disabled
we dropped the buffers. Then planes happened and everything got messy.

Actually I'm not really sure what the right semantics are here - in the
atomic helpers I don't disable planes/framebuffers. Which is consistent
with the legacy plane interface, but not consistent with the legacy
setCrtc ioctl.

Anyone has a good idea how to handle all this properly?
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch