RE: [PATCH] drm/i915/display: Add WA_14018221282

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

On Fri, 08 Nov 2024, "Golani, Mitulkumar Ajitkumar" <mitulkumar.ajitkumar.golani@intel.com> wrote:
>> -----Original Message-----
>> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of
>> Nemesa Garg
>> Sent: 08 November 2024 13:31
>> To: intel-gfx@lists.freedesktop.org
>> Cc: Garg, Nemesa <nemesa.garg@intel.com>; Kulkarni@freedesktop.org;
>> Kulkarni, Vandita <vandita.kulkarni@intel.com>
>> Subject: [PATCH] drm/i915/display: Add WA_14018221282
>> 
>> It was observed that the first write to DKL DP Mode register was not taking
>> effect, hence rewrite this register.
>> 
>> Signed-off-by: Nemesa Garg <nemesa.garg@intel.com>
>> Signed-off-by: Kulkarni, Vandita <vandita.kulkarni@intel.com>
>> ---
>>  drivers/gpu/drm/i915/display/intel_ddi.c | 14 ++++++++++++++
>>  1 file changed, 14 insertions(+)
>> 
>> diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
>> b/drivers/gpu/drm/i915/display/intel_ddi.c
>> index 769bd1f26db2..16a1d18f3aa1 100644
>> --- a/drivers/gpu/drm/i915/display/intel_ddi.c
>> +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
>> @@ -2104,6 +2104,16 @@ void
>> intel_ddi_sanitize_encoder_pll_mapping(struct intel_encoder *encoder)
>>  	encoder->disable_clock(encoder);
>>  }
>> 
>> +static void
>> +tgl_wa_14018221282(struct drm_i915_private *dev_priv, enum tc_port
>> tc_port,
>
> 1. I recommend, Need to think on naming here, as doesn't clarify on anything.

Yes please everyone stop with the madness of naming functions
bla_bla_wa_124235432().

BR,
Jani.


> 2. Also adding on thought to have pre-check of return if values are already updated.
>
>> +		   u32 ln0, u32 ln1)
>> +{
>> +	if (ln0 != intel_dkl_phy_read(dev_priv, DKL_DP_MODE(tc_port, 0)))
>> +		intel_dkl_phy_write(dev_priv, DKL_DP_MODE(tc_port, 0),
>> ln0);
>> +	if (ln1 != intel_dkl_phy_read(dev_priv, DKL_DP_MODE(tc_port, 1)))
>> +		intel_dkl_phy_write(dev_priv, DKL_DP_MODE(tc_port, 1),
>> ln1); }
>> +
>>  static void
>>  icl_program_mg_dp_mode(struct intel_digital_port *dig_port,
>>  		       const struct intel_crtc_state *crtc_state) @@ -2185,6
>> +2195,10 @@ icl_program_mg_dp_mode(struct intel_digital_port *dig_port,
>>  	if (DISPLAY_VER(dev_priv) >= 12) {
>>  		intel_dkl_phy_write(dev_priv, DKL_DP_MODE(tc_port, 0),
>> ln0);
>>  		intel_dkl_phy_write(dev_priv, DKL_DP_MODE(tc_port, 1),
>> ln1);
>> +		 /* WA_14018221282 */
>> +		if (DISPLAY_VER(dev_priv) == 12)
>> +			tgl_wa_14018221282(dev_priv, tc_port, ln0, ln1);
>
> Always use the display local var when possible. DISPLAY_VER(display)
>
>> +
>>  	} else {
>>  		intel_de_write(dev_priv, MG_DP_MODE(0, tc_port), ln0);
>>  		intel_de_write(dev_priv, MG_DP_MODE(1, tc_port), ln1);
>> --
>> 2.25.1
>

-- 
Jani Nikula, Intel