Re: [PATCH 2/2] drm/i915: Ignore long hpds on eDP ports

Jani Nikula
2014-10-22T13:42:57Z

On Tue, 21 Oct 2014, Daniel Vetter <daniel@ffwll.ch> wrote:
> On Fri, Oct 17, 2014 at 09:08:28AM -0700, Todd Previte wrote:
>>
>> On 10/17/2014 1:43 AM, Ville Syrjälä wrote:
>> >On Thu, Oct 16, 2014 at 12:38:55PM -0700, Todd Previte wrote:
>> >>On 10/16/2014 10:46 AM, ville.syrjala@linux.intel.com wrote:
>> >>>From: Ville Syrjälä <ville.syrjala@linux.intel.com>
>> >>>
>> >>>Turning vdd on/off can generate a long hpd pulse on eDP ports. In order
>> >>>to handle hpd we would need to turn on vdd to perform aux transfers.
>> >>>This would lead to an endless cycle of
>> >>>"vdd off -> long hpd -> vdd on -> detect -> vdd off -> ..."
>> >>>
>> >>>So ignore long hpd pulses on eDP ports. eDP panels should be physically
>> >>>tied to the machine anyway so they should not actually disappear and
>> >>>thus don't need long hpd handling. Short hpds are still needed for link
>> >>>re-train and whatnot so we can't just turn off the hpd interrupt
>> >>>entirely for eDP ports. Perhaps we could turn it off whenever the panel
>> >>>is disabled, but just ignoring the long hpd seems sufficient.
>> >>>
>> >>>Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>

...

> Anyway, Cc: stable@vger.kernel.org and one for Jani.

Pushed both patches to drm-intel-fixes, thanks for the patches and
review.

BR,
Jani.

--
Jani Nikula, Intel Open Source Technology Center
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