Re: [PATCH 5/5] drm/i915: Make use of unused variable in hsw_write_infoframe()

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Wed, Feb 14, 2018 at 01:37:22PM +0000, Chris Wilson wrote:
> Quoting Ville Syrjälä (2018-02-14 13:33:03)
> > On Tue, Feb 13, 2018 at 04:29:17PM -0800, José Roberto de Souza wrote:
> > > data_reg was not being used but it can be used to reduce the number of
> > > calls to hsw_dip_data_reg() and just increment the reg by the size of
> > > uint32.
> > > 
> > > Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/intel_hdmi.c | 12 ++++--------
> > >  1 file changed, 4 insertions(+), 8 deletions(-)
> > > 
> > > diff --git a/drivers/gpu/drm/i915/intel_hdmi.c b/drivers/gpu/drm/i915/intel_hdmi.c
> > > index f5d7bfb43006..ef258eac8ae8 100644
> > > --- a/drivers/gpu/drm/i915/intel_hdmi.c
> > > +++ b/drivers/gpu/drm/i915/intel_hdmi.c
> > > @@ -393,15 +393,11 @@ static void hsw_write_infoframe(struct drm_encoder *encoder,
> > >       I915_WRITE(ctl_reg, val);
> > >  
> > >       mmiowb();
> 
> mmiowb() is just a compiler barrier on x86, and meaningless wrt to our
> uncached mmio. If you need a full mmio barrier, use POSTING_READ().

Yeah, someone should nuke all the mmiowb()s from the infoframe code.
I still don't understand what they were supposed to achieve.

-- 
Ville Syrjälä
Intel OTC
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