Re: [PATCH] drm/i915/skl: Add module parameter to select edp vswing table

Jindal, Sonika
2015-05-06T05:43:36Z

On 5/5/2015 7:28 PM, Jani Nikula wrote:
> On Tue, 05 May 2015, Damien Lespiau <damien.lespiau@intel.com> wrote:
>> On Tue, May 05, 2015 at 02:39:48PM +0300, Jani Nikula wrote:
>>> There's still the question whether we can default to using the vbt value
>>> if that can be broken...
>>
>> This is a workaround for SDPs loaded with a "default" VBT which doesn't
>> correspond to the full fleet of SPDs. For actual product, it's really
>> expected to have a VBT with a correct low vswing bit set, otherwise the
>> panel won't lit up (even on Windows!).
>>
>> It's probably a good idea to add a comment saying that's it's a
>> workaround for early platform with generic-ish VBT. Something that we
>> should remove in a bit.
>
> Thanks for the clarification, Damien. That settles the default then. I'd
> still like the module parameter to be effective even if changed runtime.
>
This is used while preparing ddi buffers to program ddi_buf_trans during
driver load. It will not really have any effect at runtime until power
well is disabled/re-enabled.
PLease let me know if you still see the need of moving the check
directly in prepare_ddi_buffers.

Regards,
Sonika
> BR,
> Jani.
>
>
>
>>
>> --
>> Damien
>