[Intel-gfx] [PATCH] drm/i915: Update bits to check in device class from VBT to detect eDP

[Kumar, Shobhit]

On 6/6/2014 9:33 AM, Kumar, Shobhit wrote:
> On 6/5/2014 9:34 PM, Jesse Barnes wrote:
>> On Thu, 5 Jun 2014 16:09:29 +0300
>> Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
>>
>>> On Thu, Jun 05, 2014 at 06:25:13PM +0530, Shobhit Kumar wrote:
>>>> The DEVICE_TYPE_eDP has been changed to 0x1806 in case of BYT which
>>>> can causes wrong detection failures for eDP. Reduce the number of bits
>>>> of interest in DEVICE_TYPE_eDP_BITS to just check most relevant and
>>>> conclusive ones and ensure they are set in device_class from VBT. This
>>>> will ensure that eDP detection works across platforms
>>>
>>> The current bits will match correctly for 0x1806. I don't have a problem
>>> with the patch per-say but would be nice to know what the troublesome
>>> device type really was, if indeed there was one. I'm just slightly
>>> worried that we might start to get false positives on some platforms if
>>> we make it too relaxed.
>>
>> Still waiting for results, but
>> https://bugs.freedesktop.org/show_bug.cgi?id=78795 was what motivated
>> this.
>>
>
> Yeah and update from Jesse that forcefully returning true from the
> function make things work, I assumed this is the reason, without really
> checking that even the old values will result DEVIVE_TYPE_eDP &
> DEVICE_TYPE_eDP_BITS = 0x1806 :)
>
> Nevertheless I still feel that a simplified bit mask is good to have. We
> need to check further on this issue Jesse. Let me know once you have
> results. It would be still better to spit out the device_type being read
> from VBT as a log to confirm that indeed it is coming as 0x1806 or can
> just ask to get the opregion dump from debugfs and we can check ourselves.

I see above are already been asked in BZ. Will track there for updates.

Regards
Shobhit