[Intel-gfx] [PATCH] drm/i915: Check for a change in fb size, and reconfigure the pipe

[Chris Wilson]

On Tue, 13 Nov 2012 14:42:36 +0200, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> On Tue, Nov 13, 2012 at 12:15:10PM +0000, Chris Wilson wrote:
> > In the slightly unusual case where the pipe is programmed to the same
> > modeline, but the framebuffer is a new size, we need to resetup the
> > panel fitter as appropriate and this requires a full modeset. This can
> > only occur currently as part of the BIOS takeover where there are
> > slightly different semantics governing how the panel fitter and
> > framebuffer is programmed relative to the modeline.
> 
> Hmm. I don't get it. Why would the framebuffer size affect the panel
> fitter configuration?

The BIOS uses fb->(width,height) to program PIPESRC, we use
mode->[hv]display. The BIOS's semantics makes more sense and is
ultimately more flexible - especially if we do end up exposing more
information to userspace to solve the under/overscan issue using the
panel fitter.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre