[Intel-gfx] HDMI on D525 detected as LVDS (Was: Re: YCbCr colourspace output)

[Kenneth Graunke]

On 03/28/2011 04:51 AM, Steven Newbury wrote:
> ----- Original message -----
>> I'm connecting a D525 (Pineview) based system to an older "HD"
>> (1366x768) Phillips TV. I has a DVI connector for HD input, but whether
>> I connect it using the VGA->DVI or HDMI->DVI the TV detects the
>> incomming signal as from a PC and selects a "XGA" mode, limiting the
>> screen format to aspects and resolutions it expects a PC to use; like
>> 640x480, 800x600, 1024x768 4:3/16:10 @60Hz (always with black borders),
>> even though the TV officially supports HDTV 720p,1080i 50/60Hz etc.. I
>> suspect the issue lies in the assumption that HDTV equipment would have
>> a YCbCr colourspace.
>>
>> Now my question is, since I can't really modify the TV firmware, is it
>> possible to add YCbCr output to the driver, assuming the chip supports
>> it?
>
> Okay, it's even weirder than I thought!
>
> Further testing has shown that with an analogue RGB input the frame always has a left/right borders (making it 16:10 when in "wide screen") and are restricted to 640x480, 800x600 and 1024x768, whilst the DVI-D input seems to be more resonable, except the BIOS on my board insists on configuring the HDMI port as an LVDS with BIOS configured mode timings.  This wouldn't be too bad except the fixed mode in the BIOS for the native panel size (1366x768) gives a mode shifted significantly to the left (off the screen) and while the 1280x720 fits fine, the TV does a really awful job of scaling!
>
> I'm thinking this board must have an LVDS->HDMI converter so it wouldn't be suprising the driver treats it this way, even so it would be really handy to have an override to allow mode setting to adjust the apparent panel mode and so present such hardware in a useful fasion to userspace.

Yes. I'm 99% positive that all "HDMI" on Pineview is actually done 
through LVDS->HDMI converters.  Pineview doesn't natively support HDMI.

> Am I missing something, or does KMS only accept the BIOS provided panel timings?