Re: [PATCH 05/12] drm/i915/dp: Add crtc state for AS SDP transmission line

["Nautiyal, Ankit K" <ankit.k.nautiyal@intel.com>]

On 4/13/2026 2:06 PM, Jani Nikula wrote:
> On Mon, 13 Apr 2026, Ankit Nautiyal <ankit.k.nautiyal@intel.com> wrote:
>> The Adaptive Sync SDP is currently the only DisplayPort SDP with a
>> programmable transmission line. Store the AS SDP transmission line
>> in the crtc state and include it in the pipe configuration comparison.
>>
>> This provides a common place for SDP transmission lines and paves the way
>> for supporting additional SDP TL programming, including the common base
>> SDP transmission line introduced with Xe3p_lpd.
>>
>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
>> ---
>>   drivers/gpu/drm/i915/display/intel_display.c       | 2 ++
>>   drivers/gpu/drm/i915/display/intel_display_types.h | 8 ++++++++
>>   2 files changed, 10 insertions(+)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_display.c b/drivers/gpu/drm/i915/display/intel_display.c
>> index 10b6c6fcb03f..c66541f26a09 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display.c
>> +++ b/drivers/gpu/drm/i915/display/intel_display.c
>> @@ -5434,6 +5434,8 @@ intel_pipe_config_compare(const struct intel_crtc_state *current_config,
>>   	}
>>   	PIPE_CONF_CHECK_DP_VSC_SDP(vsc);
>>   
>> +	PIPE_CONF_CHECK_I(dp_sdp_tl.as);
>> +
> Too short, too many acronyms.

Hmm I can make it `dp_sdp_transmission_line` or just 
`sdp_transmission_line` instead of `dp_sdp_tl`.

Instead of `as` I can use `adaptive_sync`, but then it will become an 
odd one out, unless we want to expand pps, vsc, gmp and all too.

I was thinking of as_sdp too, but then that is trading one acronym with 
other and also duplicate `sdp` in the naming.


>
>>   	PIPE_CONF_CHECK_X(sync_mode_slaves_mask);
>>   	PIPE_CONF_CHECK_I(master_transcoder);
>>   	PIPE_CONF_CHECK_X(joiner_pipes);
>> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h b/drivers/gpu/drm/i915/display/intel_display_types.h
>> index e2496db1642a..f58454c23859 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
>> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
>> @@ -1298,6 +1298,14 @@ struct intel_crtc_state {
>>   		struct drm_dp_as_sdp as_sdp;
>>   	} infoframes;
>>   
>> +	struct {
>> +		/*
>> +		 * SDP Transmission line, relative to the Vtotal.
>> +		 * The programmed transmit line is (Vtotal - value)
>> +		 */
>> +		u16 as;
>> +	} dp_sdp_tl;
> Why would this deserve to be a top level sub-struct in the crtc state?


Hmm.. the struct is designed to collect all SDP transmission lines (not 
just AS, as mentioned in the commit message). It made sense to me to add 
a separate struct for storing all SDP transmission lines.

I am open to suggestion for a new place to store this though.


Regards,

Ankit


>
>> +
>>   	u8 eld[MAX_ELD_BYTES];
>>   
>>   	/* HDMI scrambling status */