[Intel-gfx] [PATCH 5/5] drm/i915: Add SPLL sharing support for DDI

[Ville Syrjälä]

On Fri, Feb 28, 2014 at 06:40:22PM -0300, Paulo Zanoni wrote:
> Hi
> 
> 2014-02-27 9:23 GMT-03:00  <ville.syrjala at linux.intel.com>:
> > From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> >
> > Write some theoretical SPLL sharing support for DDI. Currently that will
> > never happens since we never use SPLL for anything but FDI. But having
> > the code there makes it easier if we ever want to do it, and it might
> > excercise the PLL sharing code a bit more.
> 
> One thing is that if we ever want to use SSC on eDP/DP/HDMI, we will
> want to use either SPLL or WRPLL instead of LCPLL. I always wanted to
> implement this, and recently I saw a bug that made me think about it
> again.
> 
> So instead of this patch, why don't you write support to use SSC when
> requested? We could do this through some i915.use_ssc command line
> option that would just try to force SSC on everything, or maybe a
> "debug connector property", or debugfs, or anything you might want.
> With this, you would be able to actually test your patches, and we'd
> have a useful feature.
> 
> If you disagree, please just say "no" and then I'll go back to review
> this patch :)

I think improving the PLL selection code should be a separate patch.
IIRC I even said as much in the cover letter.

-- 
Ville Syrjälä
Intel OTC