[PATCH v4 2/2] drm: Add HDMI 2.0 VIC support for AVI info-frames

[Jose Abreu]

Hi Ville,


On 23-03-2017 15:45, Ville Syrjälä wrote:
> On Thu, Mar 23, 2017 at 03:28:29PM +0000, Jose Abreu wrote:
>> Hi Shashank,
>>
>>
>> On 23-03-2017 15:14, Shashank Sharma wrote:
>>> HDMI 1.4b support the CEA video modes as per range of CEA-861-D (VIC 1-64).
>>> For any other mode, the VIC filed in AVI infoframes should be 0.
>>> HDMI 2.0 sinks, support video modes range as per CEA-861-F spec, which is
>>> extended to (VIC 1-107).
>>>
>>> This patch adds a bool input variable, which indicates if the connected
>>> sink is a HDMI 2.0 sink or not. This will make sure that we don't pass a
>>> HDMI 2.0 VIC to a HDMI 1.4 sink.
>>>
>>> This patch touches all drm drivers, who are callers of this function
>>> drm_hdmi_avi_infoframe_from_display_mode but to make sure there is
>>> no change in current behavior, is_hdmi2 is kept as false.
>>>
>>> In case of I915 driver, this patch checks the connector->display_info
>>> to check if the connected display is HDMI 2.0.
>>>
>>> Cc: Ville Syrjala <ville.syrjala at linux.intel.com>
>>> Cc: Jose Abreu <jose.abreu at synopsys.com>
>>> Cc: Andrzej Hajda <a.hajda at samsung.com>
>>> Cc: Alex Deucher <alexander.deucher at amd.com>
>>> Cc: Daniel Vetter <daniel.vetter at intel.com>
>>>
>>> PS: This patch touches a few lines in few files, which were
>>> already above 80 char, so checkpatch gives 80 char warning again.
>>> - gpu/drm/omapdrm/omap_encoder.c
>>> - gpu/drm/i915/intel_sdvo.c
>>>
>>> Signed-off-by: Shashank Sharma <shashank.sharma at intel.com>
>>> ---
>>>  drivers/gpu/drm/amd/amdgpu/dce_v10_0.c    |  2 +-
>>>  drivers/gpu/drm/amd/amdgpu/dce_v11_0.c    |  2 +-
>>>  drivers/gpu/drm/amd/amdgpu/dce_v8_0.c     |  2 +-
>>>  drivers/gpu/drm/bridge/analogix-anx78xx.c |  3 ++-
>>>  drivers/gpu/drm/bridge/sii902x.c          |  2 +-
>>>  drivers/gpu/drm/bridge/synopsys/dw-hdmi.c |  2 +-
>>>  drivers/gpu/drm/drm_edid.c                | 12 +++++++++++-
>>>  drivers/gpu/drm/exynos/exynos_hdmi.c      |  2 +-
>>>  drivers/gpu/drm/i2c/tda998x_drv.c         |  2 +-
>>>  drivers/gpu/drm/i915/intel_hdmi.c         |  5 ++++-
>>>  drivers/gpu/drm/i915/intel_sdvo.c         |  3 ++-
>>>  drivers/gpu/drm/mediatek/mtk_hdmi.c       |  2 +-
>>>  drivers/gpu/drm/omapdrm/omap_encoder.c    |  3 ++-
>>>  drivers/gpu/drm/radeon/radeon_audio.c     |  2 +-
>>>  drivers/gpu/drm/rockchip/inno_hdmi.c      |  2 +-
>>>  drivers/gpu/drm/sti/sti_hdmi.c            |  2 +-
>>>  drivers/gpu/drm/tegra/hdmi.c              |  2 +-
>>>  drivers/gpu/drm/tegra/sor.c               |  2 +-
>>>  drivers/gpu/drm/vc4/vc4_hdmi.c            |  2 +-
>>>  drivers/gpu/drm/zte/zx_hdmi.c             |  2 +-
>>>  include/drm/drm_edid.h                    |  3 ++-
>>>  21 files changed, 38 insertions(+), 21 deletions(-)
>>>
>> [snip]
>>
>>> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>> index af93f7a..5ff2886 100644
>>> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
>>> @@ -1146,7 +1146,7 @@ static void hdmi_config_AVI(struct dw_hdmi *hdmi, struct drm_display_mode *mode)
>>>  	u8 val;
>>>  
>>>  	/* Initialise info frame from DRM mode */
>>> -	drm_hdmi_avi_infoframe_from_display_mode(&frame, mode);
>>> +	drm_hdmi_avi_infoframe_from_display_mode(&frame, mode, false);
>>>  
>>>  	if (hdmi->hdmi_data.enc_out_format == YCBCR444)
>>>  		frame.colorspace = HDMI_COLORSPACE_YUV444;
>>>
>> dw-hdmi controller has full support for HDMI 2.0 features. It all
>> depends on the platform it is integrated.
>>
>> I think adding a parameter to
>> drm_hdmi_avi_infoframe_from_display_mode is not the best idea
>> because of this case: A bridge can have support for HDMI 2.0
>> features but the platform may limit this support. I guess it can
>> happen in other drivers too.
> Your driver is in full control of what gets passed here. So I don't see
> why that would be a problem.
>
> Also this doesn't really have anything to do with the capabilities of
> the source. All we want to make sure is that we don't send a VIC the
> sink will not understand.
>

But the driver is not aware of the platform limitations, its
generic to the controller only. We could add a field in pdata
which tells if platform is HDMI 2.0+ but what about other bridge
drivers or HDMI drivers? They will have to replicate the same
thing also.

Best regards,
Jose Miguel Abreu