[Intel-gfx] [PATCH] drm/i915/edp: Only use alternate fixed mode when requested

[Chris Wilson]

Quoting clinton.a.taylor at intel.com (2018-04-12 00:13:26)
> From: Clint Taylor <clinton.a.taylor at intel.com>
> 
> In commit dc911f5bd8aa ("drm/i915/edp: Allow alternate fixed mode for eDP
> if available."), the patch was always selecting the alternate refresh rate
> even though user space was asking for the higher rate. This patch adds a
> check for vrefresh rate as well as the rest of the mode geometry.
> 
> V2: use clock instead of vrefresh for compare.
> 
> Fixes: dc911f5bd8aac ("Allow alternate fixed mode for eDP if available.")
> Cc: David Weinehall <david.weinehall at linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Signed-off-by: Clint Taylor <clinton.a.taylor at intel.com>

Still leaves the other discussion point in the other thread unresolved.
The fields are supplied by the user and can be arbitrary, so if they
request a clock for a 30Hz mode, instead of using the 40Hz alternative,
we use the 60Hz normal mode (by way of example). Is equality always the
best choice here?
-Chris