[RFC 09/13] drm/edid: Parse DSC1.2 cap fields from HFVSDB block

[Nautiyal, Ankit K]

On 10/19/2020 4:31 AM, Shankar, Uma wrote:
>
>> -----Original Message-----
>> From: Nautiyal, Ankit K <ankit.k.nautiyal at intel.com>
>> Sent: Thursday, October 15, 2020 4:23 PM
>> To: intel-gfx at lists.freedesktop.org
>> Cc: dri-devel at lists.freedesktop.org; Shankar, Uma <uma.shankar at intel.com>;
>> Kulkarni, Vandita <vandita.kulkarni at intel.com>; ville.syrjala at linux.intel.com;
>> Sharma, Swati2 <swati2.sharma at intel.com>
>> Subject: [RFC 09/13] drm/edid: Parse DSC1.2 cap fields from HFVSDB block
> Move this also to beginning of series along with all DRM helpers.


Agreed will move this with other DRM helpers.

>
>> This patch parses HFVSDB fields for DSC1.2 capabilities of an
>> HDMI2.1 sink. These fields are required by a source to understand the DSC
>> capability of the sink, to set appropriate PPS parameters, before transmitting
>> compressed data stream.
>>
>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>
>> ---
>>   drivers/gpu/drm/drm_edid.c  | 19 +++++++++++++++++++
>> include/drm/drm_connector.h | 32 ++++++++++++++++++++++++++++++++
>>   2 files changed, 51 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c index
>> 8afb136e73f5..feee19657a7a 100644
>> --- a/drivers/gpu/drm/drm_edid.c
>> +++ b/drivers/gpu/drm/drm_edid.c
>> @@ -4889,10 +4889,29 @@ static void
>> drm_parse_hdmi_21_additional_fields(struct drm_connector *connector,  {
>>   struct drm_hdmi_info *hdmi = &connector->display_info.hdmi;
>>   u8 max_frl_rate;
>> +u8 dsc_max_frl_rate;
>>
>>   max_frl_rate = db[7] & DRM_EDID_MAX_FRL_RATE_MASK;
>>   drm_get_max_frl_rate(max_frl_rate, &hdmi->max_lanes,
>>        &hdmi->max_frl_rate_per_lane);
>> +
>> +hdmi->dsc_1p2 = db[11] & DRM_EDID_DSC_1P2;
> We should right shift them as well to get right values.

You are right, For MAX_FRL_RATE and DSC_MAX_FRL_RATE_MASK given below, 
we need to rshift by 4 for getting correct values.

I had missed that in this patch. Will take care in the next version.

But for others there are only 1 bit, we are just storing these as bool, 
if the appropriate bit is set.


>
>> +        hdmi->dsc_native_420 = db[11] & DRM_EDID_DSC_NATIVE_420;
> Same here. Also Alignment is off.


Will fix the alignment in next version.

>
>> +hdmi->dsc_all_bpp = db[11] & DRM_EDID_DSC_ALL_BPP;
>> +
>> +if (db[11] & DRM_EDID_DSC_16BPC)
>> +hdmi->dsc_bpc_supported = 16;
>> +else if (db[11] & DRM_EDID_DSC_12BPC)
>> +hdmi->dsc_bpc_supported = 12;
>> +else if (db[11] & DRM_EDID_DSC_10BPC)
>> +hdmi->dsc_bpc_supported = 10;
>> +else
>> +hdmi->dsc_bpc_supported = 0;
>> +
>> +dsc_max_frl_rate = db[12] & DRM_EDID_DSC_MAX_FRL_RATE;
> This will not give correct value. Fix it.

As mentioned above, will fix this in next version.


>
>> +drm_get_max_frl_rate(dsc_max_frl_rate, &hdmi->dsc_max_lanes,
>> +     &hdmi->dsc_max_frl_rate_per_lane);
>> +hdmi->dsc_total_chunk_kbytes = db[13] &
>> +DRM_EDID_DSC_TOTAL_CHUNK_KBYTES;
>>   }
>>
>>   static void drm_parse_ycbcr420_deep_color_info(struct drm_connector
>> *connector, diff --git a/include/drm/drm_connector.h
>> b/include/drm/drm_connector.h index f351bf10c076..7100012f9c0f 100644
>> --- a/include/drm/drm_connector.h
>> +++ b/include/drm/drm_connector.h
>> @@ -213,6 +213,38 @@ struct drm_hdmi_info {
>>
>>   /** @max_lanes: supported by sink */
>>   u8 max_lanes;
>> +
>> +/** @dsc_1p2: flag for dsc1.2 support by sink */
>> +bool dsc_1p2;
> Add a struct for all these HDMI dsc params.


Makes sense, will add a new struct for HDMI dsc parameters read for DSC 
supported by a given HDMI sink.

Thanks & Regards,

Ankit

>
>> +
>> +/** @dsc_native_420: Does sink support DSC with 4:2:0 compression */
>> +bool dsc_native_420;
>> +
>> +/**
>> + * @dsc_all_bpp: Does sink support all bpp with 4:4:4: or 4:2:2
>> + * compressed formats
>> + */
>> +bool dsc_all_bpp;
>> +
>> +/**
>> + * @dsc_bpc_supported: compressed bpc supported by sink : 10, 12 or 16
>> bpc
>> + */
>> +u8 dsc_bpc_supported;
>> +
>> +/** @dsc_max_slices: maximum number of Horizontal slices supported
>> by */
>> +u8 dsc_max_slices;
>> +
>> +/** @dsc_clk_per_slice : max pixel clock in MHz supported per slice */
>> +u8 dsc_clk_per_slice;
>> +
>> +/** @dsc_max_lanes : dsc max lanes supported for Fixed rate Link
>> training */
>> +u8 dsc_max_lanes;
>> +
>> +/** @dsc_max_frl_rate_per_lane : maximum frl rate with DSC per lane */
>> +u8 dsc_max_frl_rate_per_lane;
>> +
>> +/** @dsc_total_chunk_kbytes: max size of chunks in KBs supported per
>> line*/
>> +u8 dsc_total_chunk_kbytes;
>>   };
>>
>>   /**
>> --
>> 2.17.1