Re: [Intel-gfx] [RFC 04/13] drm/i915: Capture max frl rate for PCON in dfp cap structure

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

On 10/19/2020 3:11 AM, Shankar, Uma wrote:
>
>> -----Original Message-----
>> From: Nautiyal, Ankit K <ankit.k.nautiyal@intel.com>
>> Sent: Thursday, October 15, 2020 4:23 PM
>> To: intel-gfx@lists.freedesktop.org
>> Cc: dri-devel@lists.freedesktop.org; Shankar, Uma <uma.shankar@intel.com>;
>> Kulkarni, Vandita <vandita.kulkarni@intel.com>; ville.syrjala@linux.intel.com;
>> Sharma, Swati2 <swati2.sharma@intel.com>
>> Subject: [RFC 04/13] drm/i915: Capture max frl rate for PCON in dfp cap structure
>>
>> HDMI2.1 PCON advertises Max FRL bandwidth supported by the PCON and by the
>> sink.
>>
>> This patch captures these in dfp cap structure in intel_dp and uses these to
>> prune connector modes that cannot be supported by the PCON and sink FRL
>> bandwidth.
>>
>> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com>
>> ---
>>   .../drm/i915/display/intel_display_types.h    |  1 +
>>   drivers/gpu/drm/i915/display/intel_dp.c       | 33 +++++++++++++++++--
>>   2 files changed, 32 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
>> b/drivers/gpu/drm/i915/display/intel_display_types.h
>> index 0b5df8e44966..e2f58d0575a2 100644
>> --- a/drivers/gpu/drm/i915/display/intel_display_types.h
>> +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
>> @@ -1398,6 +1398,7 @@ struct intel_dp {
>>   struct {
>>   int min_tmds_clock, max_tmds_clock;
>>   int max_dotclock;
>> +int pcon_max_frl, sink_max_frl;
> Append it with bw or rate.


Agreed, will add 'bw' for clarity.

>
>>   u8 max_bpc;
>>   bool ycbcr_444_to_420;
>>   } dfp;
>> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
>> b/drivers/gpu/drm/i915/display/intel_dp.c
>> index 0902a9aeeda1..cd6934f28f32 100644
>> --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> @@ -683,6 +683,24 @@ intel_dp_mode_valid_downstream(struct
>> intel_connector *connector,
>>   const struct drm_display_info *info = &connector->base.display_info;
>>   int tmds_clock;
>>
>> +/* If PCON and HDMI2.1 sink both support FRL MODE, check FRL
> Use multi line comment style.

Agreed. Will take care in next version.


>
>> + * bandwidth constraints.
>> + */
>> +if (intel_dp->dfp.pcon_max_frl) {
>> +int target_bw;
>> +int max_frl_bw;
>> +int bpp = intel_dp_mode_min_output_bpp(&connector->base,
>> mode);
>> +
>> +target_bw = bpp * DIV_ROUND_UP(target_clock, 1000000);
> To avoid any roundup errors, it would be good to multiple max_frl_bw by 1000000 than dividing target_clock

Alright. Will take care of this in next version.


Thanks & Regards,

Ankit

>
>> +
>> +max_frl_bw = min(intel_dp->dfp.pcon_max_frl,
>> + intel_dp->dfp.sink_max_frl);
>> +if (target_bw > max_frl_bw)
>> +return MODE_CLOCK_HIGH;
>> +
>> +return MODE_OK;
>> +}
>> +
>>   if (intel_dp->dfp.max_dotclock &&
>>       target_clock > intel_dp->dfp.max_dotclock)
>>   return MODE_CLOCK_HIGH;
>> @@ -6383,13 +6401,21 @@ intel_dp_update_dfp(struct intel_dp *intel_dp,
>>    intel_dp->downstream_ports,
>>    edid);
>>
>> +intel_dp->dfp.pcon_max_frl =
>> +drm_dp_get_pcon_max_frl_bw(intel_dp->dpcd,
>> +   intel_dp->downstream_ports);
>> +
>> +intel_dp->dfp.sink_max_frl =
>> +drm_dp_get_hdmi_max_frl_bw(&intel_dp->aux);
>> +
>>   drm_dbg_kms(&i915->drm,
>> -    "[CONNECTOR:%d:%s] DFP max bpc %d, max dotclock %d,
>> TMDS clock %d-%d\n",
>> +    "[CONNECTOR:%d:%s] DFP max bpc %d, max dotclock %d,
>> TMDS clock
>> +%d-%d, PCON Max FRL BW %dGbps, Sink Max FRL BW %dGbps\n",
>>       connector->base.base.id, connector->base.name,
>>       intel_dp->dfp.max_bpc,
>>       intel_dp->dfp.max_dotclock,
>>       intel_dp->dfp.min_tmds_clock,
>> -    intel_dp->dfp.max_tmds_clock);
>> +    intel_dp->dfp.max_tmds_clock,
>> +    intel_dp->dfp.pcon_max_frl,
>> +    intel_dp->dfp.sink_max_frl);
>>   }
>>
>>   static void
>> @@ -6479,6 +6505,9 @@ intel_dp_unset_edid(struct intel_dp *intel_dp)
>>   intel_dp->dfp.min_tmds_clock = 0;
>>   intel_dp->dfp.max_tmds_clock = 0;
>>
>> +intel_dp->dfp.pcon_max_frl = 0;
>> +intel_dp->dfp.sink_max_frl = 0;
>> +
>>   intel_dp->dfp.ycbcr_444_to_420 = false;
>>   connector->base.ycbcr_420_allowed = false;  }
>> --
>> 2.17.1
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