[Intel-gfx] [PATCH 3/7] drm/i915: Fixup pfit disabling for gen2/3

[Chris Wilson]

On Thu, Apr 11, 2013 at 04:29:06PM +0200, Daniel Vetter wrote:
> The recent rework of the pfit handling didn't take into account that
> the panel fitter is fixed to pipe B:
> 
> commit 24a1f16de97c4cf0029d9acd04be06db32208726
> Author: Mika Kuoppala <mika.kuoppala at linux.intel.com>
> Date:   Fri Feb 8 16:35:37 2013 +0200
> 
>     drm/i915: disable shared panel fitter for pipe
> 
> Fix this up by properly computing the pipe the pfit is on. Also
> extract the logic into its own function, add a debug assert to check
> that the pipe is off (mostly just documentation) and add some debug
> output.
> 
> If pipe A was disabled after pipe B was set up, the panel fitter will
> be disabled. Now most userspace doesn't do modesets in this order,
> which is why I couldn't ever reproduce this and why it took me so long
> to figure out.
> 
> We really need hw state readout and check support for the pannel
> fitter ...
> 
> Reported-by: Hans de Bruin <jmdebruin at xmsnet.nl>
> Cc: Mika Kuoppala <mika.kuoppala at intel.com>
> Cc: Hans de Bruin <jmdebruin at xmsnet.nl>
> References: http://permalink.gmane.org/gmane.comp.freedesktop.xorg.drivers.intel/19049
> Signed-off-by: Daniel Vetter <daniel.vetter at ffwll.ch>

Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre