[Intel-gfx] [PATCH 2/4] drm/dp: use more of the extended receiver cap

[Jani Nikula]

On Thu, 19 Aug 2021, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> On Fri, Aug 13, 2021 at 01:43:20PM +0300, Jani Nikula wrote:
>> Extend the use of extended receiver cap at 0x2200 to cover
>> MAIN_LINK_CHANNEL_CODING_CAP in 0x2206, in case an implementation hides
>> the DP 2.0 128b/132b channel encoding cap.
>> 
>> Cc: Manasi Navare <manasi.d.navare at intel.com>
>> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
>> ---
>>  drivers/gpu/drm/drm_dp_helper.c | 2 +-
>>  1 file changed, 1 insertion(+), 1 deletion(-)
>> 
>> diff --git a/drivers/gpu/drm/drm_dp_helper.c b/drivers/gpu/drm/drm_dp_helper.c
>> index 9b2a2961fca8..9389f92cb944 100644
>> --- a/drivers/gpu/drm/drm_dp_helper.c
>> +++ b/drivers/gpu/drm/drm_dp_helper.c
>> @@ -608,7 +608,7 @@ static u8 drm_dp_downstream_port_count(const u8 dpcd[DP_RECEIVER_CAP_SIZE])
>>  static int drm_dp_read_extended_dpcd_caps(struct drm_dp_aux *aux,
>>  					  u8 dpcd[DP_RECEIVER_CAP_SIZE])
>>  {
>> -	u8 dpcd_ext[6];
>> +	u8 dpcd_ext[DP_MAIN_LINK_CHANNEL_CODING + 1];
>
> Why are we even reading less of this than the normal receiver caps?

Good question. I forget my reasoning to only extend to what might affect
this use case. Should we extend to the size of the usual receiver caps?

BR,
Jani.


>
>>  	int ret;
>>  
>>  	/*
>> -- 
>> 2.20.1

-- 
Jani Nikula, Intel Open Source Graphics Center