[Intel-gfx] [PATCH] drm/i915: Detect invalid scanout pitches

[Chris Wilson]

On Thu, Jun 20, 2013 at 11:17:16AM +0300, Ville Syrjälä wrote:
> We already have a bit of pitch checking in intel_framebuffer_init().
> In fact there's a FIXME about pre-ilk limits there.

It looks tidier to fix that check. We still need to double check the
values though as the tiling mode is independent of the fb config and may
be changed by the user.
 
> Assuming all the planes on a specific piece of hardware have the same
> pitch limits, I'd like the checks to be live in
> intel_framebuffer_init() so that the issue gets caught as early as
> possible. For stricter per-plane limits we obviously need the checks
> in update_plane.
> 
> What I can gather from BSpec is this:
> gen2: linear/tiled 8k, (maybe DSPC tiled max 4k?)
> gen3: linear ?, tiled 8k
> gen4: linear ?, tiled 16k
> ctg: linear ?, tiled 16k
> ilk+: 32k all the way
> 
> Looking at your patch you have 16k,32k,32k for the ?s in my list.
> Otherwise your numbers seem to agree with my findings.

The only one I didn't check was the VLV addendum.
 
> So, to me it looks like all the planes do share the same limits (DSPC on
> gen2 might be a minor exception), so I think we could move all of these
> checks to intel_framebuffer_init().

Except for the rare cases where the limits may change between init and
set-base...
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre