Re: [PATCH] drm/i915/psr: simplify enable_psr handling

[Ross Zwisler]

On Fri, Dec 21, 2018 at 11:23:07AM -0800, Dhinakaran Pandiyan wrote:
> On Fri, 2018-12-21 at 10:23 -0700, Ross Zwisler wrote:
> > The following commit:
> > 
> > commit 2bdd045e3a30 ("drm/i915/psr: Check if VBT says PSR can be
> > enabled.")
> > 
> > added some code with no usable functionality.  Regardless of how the
> > psr
> > default is set up in the BDB_DRIVER_FEATURES section, if the
> > enable_psr
> > module parameter isn't specified it defaults to 0.
> Right, that was intentional and the commit message even makes a note of
> it 
> " Note: The feature currently remains disabled by default for all
> platforms irrespective of what VBT says."
> 
> 
> Anyway, we've enabled the feature by default now and the current code
> should take into account the VBT flag if the module parameter is left
> to a default value. Please check git://anongit.freedesktop.org/drm-tip
> drm-tip.

Fair enough.  It's a bad pattern to introduce dead code as a placeholder for
some future work, though.  This code has been in the tree for three major
kernel releases (v4.{18,19,20}) without providing any useful functionality.