[Intel-gfx] [PATCH] drm/i915: Don't call intel_prepare_ddi when encoder list isn't yet initialized.

[Daniel Vetter]

On Fri, Sep 25, 2015 at 04:09:56PM +0000, Vivi, Rodrigo wrote:
> On Fri, 2015-09-25 at 13:52 +0300, Jani Nikula wrote:
> > On Wed, 23 Sep 2015, Rodrigo Vivi <rodrigo.vivi at intel.com> wrote:
> > > In case something goes wrong with power well initialization we were
> > > calling
> > > intel_prepare_ddi during boot while encoder list isnt't initilized.
> > 
> > Broken record, is this a regression, what is the regressing commit,
> > or
> > if this was always broken, which commit introduced the broken
> > feature?
> 
> I believe it is broken since this call was introduced, but when
> everything goes as expected it isn't executed.
> Only in rare cases where power well initialization didn't go well and
> post call is called during init it will trigger this case.
> I don't believe this is something that a regular user of stables
> platforms should worrie though... but it is always good to protect to
> be on the safe side.

You posted a backtrace of the kernel dying in an oops. That looks pretty
serious ;-) But even if this has been broken since forever in skl we only
need to apply it to 4.3-fixes.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch