Re: [Intel-gfx] [PATCH] drm/i915/display/dp: Remove support for UHBR13.5

[Jani Nikula <jani.nikula@intel.com>]

On Thu, 22 Jun 2023, "Murthy, Arun R" <arun.r.murthy@intel.com> wrote:
>> -----Original Message-----
>> From: Nikula, Jani <jani.nikula@intel.com>
>> Sent: Wednesday, June 21, 2023 2:27 PM
>> To: Murthy, Arun R <arun.r.murthy@intel.com>; intel-
>> gfx@lists.freedesktop.org
>> Cc: Deak, Imre <imre.deak@intel.com>; Kahola, Mika
>> <mika.kahola@intel.com>; Murthy, Arun R <arun.r.murthy@intel.com>
>> Subject: Re: [PATCH] drm/i915/display/dp: Remove support for UHBR13.5
>>
>> On Tue, 20 Jun 2023, Arun R Murthy <arun.r.murthy@intel.com> wrote:
>> > As per the DP2.1 Spec support for UHBR13.5 is optional. Hence removing
>> > the support for UHBR13.5
>>
>> That's just not a proper rationale. Please explain.
>>
> Programming for UHBR10 and UHBR20 is similar compared to UHBR13.5
> As of now we have validated 10Gbps and 20Gbps. The spec also points out when 20Gbps is supported 13.5Gbps is optional so we have not validated/implemented the UHBR13.5
> Now we have the DP2.1 compatible panel is market, expecting users can come up with UHBR13.5 not working. Hence removing the support for 13.5Gbps for now.
> Maybe once we have support for UHBR13.5 in the driver we can enable this.

What's missing?

BR,
Jani.



>
> Thanks and Regards,
> Arun R Murthy
> --------------------
>> BR,
>> Jani.
>>
>>
>> > UHBR10 can be used for 6k panels.
>> >
>> > Signed-off-by: Arun R Murthy <arun.r.murthy@intel.com>
>> > ---
>> >  drivers/gpu/drm/i915/display/intel_dp.c | 2 +-
>> >  1 file changed, 1 insertion(+), 1 deletion(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
>> > b/drivers/gpu/drm/i915/display/intel_dp.c
>> > index 9f40da20e88d..54ddc953e5bc 100644
>> > --- a/drivers/gpu/drm/i915/display/intel_dp.c
>> > +++ b/drivers/gpu/drm/i915/display/intel_dp.c
>> > @@ -465,7 +465,7 @@ intel_dp_set_source_rates(struct intel_dp
>> *intel_dp)
>> >     };
>> >     static const int icl_rates[] = {
>> >             162000, 216000, 270000, 324000, 432000, 540000, 648000,
>> 810000,
>> > -           1000000, 1350000,
>> > +           1000000,
>> >     };
>> >     static const int bxt_rates[] = {
>> >             162000, 216000, 243000, 270000, 324000, 432000, 540000
>>
>> --
>> Jani Nikula, Intel Open Source Graphics Center

-- 
Jani Nikula, Intel Open Source Graphics Center