[Intel-gfx] [PATCH 2/2] drm/i915: Support for HDMI complaince HPD

[Chris Wilson]

On Tue, Aug 12, 2014 at 08:56:44PM +0530, Sharma, Shashank wrote:
> Hello Chris,
> 
> Thanks for your time and comments.
> I would like to give a brief history of the patch.
> 
> We tried to apply this optimization by default, and check all the
> EDID read based on the live status. But not all developers agreed to
> have this by default, with following reasons:
> 1. live_status was not very reliable for all platforms, so live_status
>    based solution shouldn't be added.
> 2. they dint want EDID caching to be by default, as few old platforms
>    were not even HPD capable.
> 
> So we came up with this intermediate solution to have:
> 1. Timeout based EDID caching, where cached EDID will be cleared after
>    one minute.
> 2. An alternative code flow to support HDMI compliance (will be based
>    on the live_status check, and will be only enabled for commercial
>    platforms like android) which need HDMI compliance support. So the
>    kernel command line parameter is to support the need to add this
>    alternative EDID read method.
> 
> Please le me know your opinion about this, considering the background.

I know. That is orthogonal to the tweaks I was suggesting. Also if you
feel you need to add details to your rationale, then your changelog is
incomplete.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre