[Intel-gfx] [PATCH 3/3] drm/i915: Prevent zero length "index" write

[Chris Wilson]

Quoting Ville Syrjala (2017-11-23 19:41:57)
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> The hardware always writes one or two bytes in the index portion of
> an indexed transfer. Make sure the message we send as the index
> doesn't have a zero length.
> 
> Cc: stable at vger.kernel.org
> Cc: Daniel Kurtz <djkurtz at chromium.org>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Daniel Vetter <daniel.vetter at ffwll.ch>
> Cc: Sean Paul <seanpaul at chromium.org>
> Fixes: 56f9eac05489 ("drm/i915/intel_i2c: use INDEX cycles for i2c read transactions")
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris