[Intel-gfx] [PATCH 2/2] drm/i915: don't disable DP port after a failed link training

[Chris Wilson]

On Thu, Jan 16, 2014 at 06:01:28PM +0100, Daniel Vetter wrote:
> On Thu, Jan 16, 2014 at 5:58 PM, Chris Wilson <chris at chris-wilson.co.uk> wrote:
> > On Thu, Jan 16, 2014 at 06:35:58PM +0200, Imre Deak wrote:
> >> The driver shouldn't disable the DP port itself, but let userspace do it
> >> through a modeset. See the previous patch for the reasoning.
> >
> > Eh, this occurs not just during link detection, but also during
> > intel_enable_dp, so this comment does not hold.  The biggest
> > issue of this function is that it can fail but never propagates
> > that failure, which itself breaks the users and API expectations,
> > as neither the driver or userspace is aware that it is required to
> > takeaction.
> 
> Yeah, but imo that's a separate issue - atm we kill the DP port, which
> stops the pipe, which is something our code never expects. Resulting
> in piles of funny bug reports from angry users who's machine got stuck
> because of this.

But this alone will not stop the bug reports - the display will still be
blank but kernel/userspace will continue to believe that the modeset
took place.

I did not say that the patch was not sensible, just insufficient ;-)
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre