[PATCH 03/11] drm: parse ycbcr 420 vdb block

[Sharma, Shashank]

Regards

Shashank


On 5/8/2017 9:54 PM, Ville Syrjälä wrote:
> On Fri, Apr 07, 2017 at 07:39:20PM +0300, Shashank Sharma wrote:
>> From: Jose Abreu <jose.abreu at synopsys.com>
>>
>> HDMI 2.0 spec adds support for ycbcr420 subsampled output.
>> CEA-861-F adds two new blocks in EDID, to provide information about
>> sink's support for ycbcr420 output.
>>
>> These new blocks are:
>> - ycbcr420 video data (vdb) block: video modes which can be supported
>>    only in ycbcr420 output mode.
>> - ycbcr420 video capability data (vcb) block: video modes which can be
>>    support in ycbcr420 output mode also (along with RGB, YCBCR 444/422 etc)
>>
>> This patch adds parsing and handling of ycbcr420-vdb in the DRM
>> layer.
>>
>> This patch is a modified version of Jose's RFC patch:
>> https://patchwork.kernel.org/patch/9492327/
>> so the authorship is maintained.
>>
>> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
>> Signed-off-by: Jose Abreu <joabreu at synopsys.com>
>> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
>> ---
>>   drivers/gpu/drm/drm_edid.c  | 54 +++++++++++++++++++++++++++++++++++++++++++--
>>   drivers/gpu/drm/drm_modes.c | 10 +++++++--
>>   include/drm/drm_connector.h |  1 +
>>   include/uapi/drm/drm_mode.h |  6 +++++
>>   4 files changed, 67 insertions(+), 4 deletions(-)
> <snip>
>> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
>> index 4eeda12..cef76b2 100644
>> --- a/include/drm/drm_connector.h
>> +++ b/include/drm/drm_connector.h
>> @@ -199,6 +199,7 @@ struct drm_display_info {
>>   #define DRM_COLOR_FORMAT_RGB444		(1<<0)
>>   #define DRM_COLOR_FORMAT_YCRCB444	(1<<1)
>>   #define DRM_COLOR_FORMAT_YCRCB422	(1<<2)
>> +#define DRM_COLOR_FORMAT_YCRCB420	(1<<2)
>>   
>>   	/**
>>   	 * @color_formats: HDMI Color formats, selects between RGB and YCrCb
>> diff --git a/include/uapi/drm/drm_mode.h b/include/uapi/drm/drm_mode.h
>> index 8c67fc0..1e74d8e 100644
>> --- a/include/uapi/drm/drm_mode.h
>> +++ b/include/uapi/drm/drm_mode.h
>> @@ -84,6 +84,12 @@ extern "C" {
>>   #define  DRM_MODE_FLAG_3D_L_DEPTH_GFX_GFX_DEPTH	(6<<14)
>>   #define  DRM_MODE_FLAG_3D_TOP_AND_BOTTOM	(7<<14)
>>   #define  DRM_MODE_FLAG_3D_SIDE_BY_SIDE_HALF	(8<<14)
>> +/*
>> + * HDMI 2.0
>> + */
>> +#define DRM_MODE_FLAG_420_MASK			(0x03<<23)
>> +#define  DRM_MODE_FLAG_420			(1<<23)
>> +#define  DRM_MODE_FLAG_420_ONLY			(1<<24)
> Adding those would again break the uabi. We can't add new mode flags
> without some kind of client cap.
> But I think we agreed that new user
> space visible mode flags aren't needed, and instad we can keep it all
> internal?
Yep you are right, we had decided to keep it internal, and this whole 
patch series is implemented in such a way only, to control everything 
through the HDMI output property itself.
But may be I slightly misunderstood that we shouldn't add the flags bits 
all together, and I added this flag to differentiate between YCBCR420 
and notmal modes.
Can you please suggest me on:
- how to differentiate a YCBCR420 mode with normal mode ? I still need 
to add a flag, but not expose it into uapi layer.

- Shashank