[Intel-gfx] [RFC] drm/i915/edp: use max lanes and clock for edp

[Jesse Barnes]

On Thu, 04 Sep 2014 10:53:44 +0300
Jani Nikula <jani.nikula at intel.com> wrote:

> On Tue, 02 Sep 2014, Jani Nikula <jani.nikula at intel.com> wrote:
> > On Tue, 02 Sep 2014, Jani Nikula <jani.nikula at intel.com> wrote:
> >> How about throwing this at any eDP link parameter bugs and
> >> regressions? Does it feel too much like giving up the battle?
> >
> > Fixes at least one bug...
> >
> > https://bugs.freedesktop.org/show_bug.cgi?id=79386#c15
> 
> Another
> 
> https://bugs.freedesktop.org/show_bug.cgi?id=81647#c6
> 
> >
> >> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> >> ---
> >>  drivers/gpu/drm/i915/intel_dp.c | 24 +++++++-----------------
> >>  1 file changed, 7 insertions(+), 17 deletions(-)
> >>
> >> diff --git a/drivers/gpu/drm/i915/intel_dp.c
> >> b/drivers/gpu/drm/i915/intel_dp.c index d7fc2c0e9ba8..f4248d7f64f9
> >> 100644 --- a/drivers/gpu/drm/i915/intel_dp.c
> >> +++ b/drivers/gpu/drm/i915/intel_dp.c
> >> @@ -889,23 +889,13 @@ intel_dp_compute_config(struct intel_encoder
> >> *encoder, bpp = dev_priv->vbt.edp_bpp;
> >>  		}
> >>  
> >> -		if (IS_BROADWELL(dev)) {
> >> -			/* Yes, it's an ugly hack. */
> >> -			min_lane_count = max_lane_count;
> >> -			DRM_DEBUG_KMS("forcing lane count to max
> >> (%u) on BDW\n",
> >> -				      min_lane_count);
> >> -		} else if (dev_priv->vbt.edp_lanes) {
> >> -			min_lane_count =
> >> min(dev_priv->vbt.edp_lanes,
> >> -					     max_lane_count);
> >> -			DRM_DEBUG_KMS("using min %u lanes per
> >> VBT\n",
> >> -				      min_lane_count);
> >> -		}
> >> -
> >> -		if (dev_priv->vbt.edp_rate) {
> >> -			min_clock = min(dev_priv->vbt.edp_rate >>
> >> 3, max_clock);
> >> -			DRM_DEBUG_KMS("using min %02x link bw per
> >> VBT\n",
> >> -				      bws[min_clock]);
> >> -		}
> >> +		/*
> >> +		 * Use the maximum clock and number of lanes the
> >> eDP panel
> >> +		 * advertizes being capable of. Typically these
> >> values
> >> +		 * correspond to the native resolution of the
> >> panel.
> >> +		 */
> >> +		min_lane_count = max_lane_count;
> >> +		min_clock = max_clock;
> >>  	}
> >>  
> >>  	for (; bpp >= 6*3; bpp -= 2*3) {
> >> -- 
> >> 1.9.1
> >>
> >
> > -- 
> > Jani Nikula, Intel Open Source Technology Center
> 


Then I'd say let's go for it.  We can always whitelist systems where we
can use fewer lanes (e.g. some Chromebooks).

Reviewed-by: Jesse Barnes <jbarnes at virtuousgeek.org>