[Intel-gfx] [PATCH] drm/i915: enforce bitbanging for i2c

[Daniel Vetter]

On Tue, Aug 21, 2012 at 12:03:49PM +0300, Jani Nikula wrote:
> On Tue, 21 Aug 2012, Daniel Vetter <daniel.vetter at ffwll.ch> wrote:
> > Now that we have also have a workaround for crt to fallback to
> > bitbanging in some cases and then restore gmbus again, we need to
> > ensure that we don't try to enable gmbus on broken hw (like i830M).
> > Previously only sdvo had a bit-banging fallback, and sdvo is gen3+
> > only, so no issue with that.
> >
> > Enforce this by tracking separately whether gmbus even could work.
> >
> > This issue has been introduced in
> >
> > commit f1a2f5b7c5f0941d23eef0a095c0b99bf8d051e6
> > Author: Jani Nikula <jani.nikula at intel.com>
> > Date:   Mon Aug 13 13:22:35 2012 +0300
> >
> >     drm/i915: fall back to bit-banging if GMBUS fails in CRT EDID
> >     reads
> >
> > Found by code-inspection, no bug report afaik.
> 
> I don't see how my patch could enable or try GMBUS if force_bit has been
> set to true. On i830 the first attempt will be bit-banging, as before,
> and there will be no fallback because bit-banging is already enabled.
> 
> I don't think this patch is necessary, but by all means prove me
> wrong. ;)

Right, I've missed the is_force_bit check in intel_crt_get_edid, patch is
not required.

/me hides

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