[Intel-gfx] [PATCH 3/4] drm/i915: Fix platform default aux ch for skl

[Nautiyal, Ankit K]

On 2/17/2023 6:42 PM, Ville Syrjälä wrote:
> On Fri, Feb 17, 2023 at 06:35:51PM +0530, Nautiyal, Ankit K wrote:
>> On 2/17/2023 5:32 PM, Ville Syrjälä wrote:
>>> On Fri, Feb 17, 2023 at 03:15:59PM +0530, Nautiyal, Ankit K wrote:
>>>> On 2/17/2023 4:43 AM, Ville Syrjala wrote:
>>>>> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>>>
>>>>> SKL/derivatives have DDI E but no AUX E, so we need to pick
>>>>> another aux ch as the platform default. DDI E is more or less
>>>>> the other half of DDI A, so we pick AUX A.
>>>>>
>>>>> In all other cases we should have a corresponding aux ch for
>>>>> each DDI.
>>>>>
>>>>> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>>>>> ---
>>>>>     drivers/gpu/drm/i915/display/intel_dp_aux.c | 14 ++++++++++++--
>>>>>     1 file changed, 12 insertions(+), 2 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/i915/display/intel_dp_aux.c b/drivers/gpu/drm/i915/display/intel_dp_aux.c
>>>>> index 57eb3ff187fa..96967e21c94c 100644
>>>>> --- a/drivers/gpu/drm/i915/display/intel_dp_aux.c
>>>>> +++ b/drivers/gpu/drm/i915/display/intel_dp_aux.c
>>>>> @@ -739,10 +739,20 @@ void intel_dp_aux_init(struct intel_dp *intel_dp)
>>>>>     	cpu_latency_qos_add_request(&intel_dp->pm_qos, PM_QOS_DEFAULT_VALUE);
>>>>>     }
>>>>>     
>>>>> +static enum aux_ch default_aux_ch(struct intel_encoder *encoder)
>>>>> +{
>>>>> +	struct drm_i915_private *i915 = to_i915(encoder->base.dev);
>>>>> +
>>>>> +	/* SKL has DDI E but no AUX E */
>>>>> +	if (DISPLAY_VER(i915) == 9 && encoder->port == PORT_E)
>>>>> +		return AUX_CH_A;
>>>>> +
>>>> I guess we might need to fix intel_dp_aux_init also. Wont we have
>>>> dig_port->aux_ch and intel_dp->aux_ch pointing to different things?
>>> There is no intel_dp->aux_ch.
>>>
>>>> For example for SKL and DDI E, intel_dp->aux.name will be derived from
>>>> dig_port->aux_ch i.e. AUX_CH_A but intel_dp->aux_ctl/data reg will still
>>>> point to DP_AUX_CH_CTL/DATA_E.
>>>>
>>>> Am I missing something?
>>> Everything is based on dig_port->aux_ch.
>> Yeah my bad. I think I misread and got confused. We indeed are using
>> dig_port->aux_ch, for getting aux_ctl/data reg.
>>
>> I couldnt get the exact bspec mention for SKL not having AUX E, but SKL
>> Display connection Bspec:4217 throws some light, if I am not fully off.
>>
>> Is this applicable to Canonlake too  (Bspec:14004) from Display
>> connection it does seem to have DDI E but no DP_AUX E?
> There is no Cannonlake.

Hmm. I see its only applicable to Gen 9 then.

Patch look good to me.

Reviewed-by: Ankit Nautiyal <ankit.k.nautiyal at intel.com>


Regards,

Ankit