RE: [PATCH v2 07/12] drm/i915/cx0: Remove bus reset after every c10 transaction

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

On Thu, 24 Oct 2024, "Kahola, Mika" <mika.kahola@intel.com> wrote:
>> -----Original Message-----
>> From: Intel-gfx <intel-gfx-bounces@lists.freedesktop.org> On Behalf Of Clint
>> Taylor
>> Sent: Thursday, 24 October 2024 0.47
>> To: intel-gfx@lists.freedesktop.org; intel-xe@lists.freedesktop.org
>> Subject: [PATCH v2 07/12] drm/i915/cx0: Remove bus reset after every c10
>> transaction
>> 
>> C10 phy timeouts occur on xe3lpd if the c10 bus is reset every transaction.
>> Starting with xe3lpd this is bus reset not necessary
>> 
>
> This C10/C20 bus reset was originally placed as a workaround to prevent bus timeouts. These timeouts were fixed elsewhere and therefore these are unnecessary lines.
>
> Reviewed-by: Mika Kahola <mika.kahola@intel.com>

Why no mention of the extra braces in there?

BR,
Jani.

>
>> Signed-off-by: Clint Taylor <clinton.a.taylor@intel.com>
>> ---
>>  drivers/gpu/drm/i915/display/intel_cx0_phy.c | 6 ++++--
>>  1 file changed, 4 insertions(+), 2 deletions(-)
>> 
>> diff --git a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
>> b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
>> index c1357bdb8a3b..a8966a7a9927 100644
>> --- a/drivers/gpu/drm/i915/display/intel_cx0_phy.c
>> +++ b/drivers/gpu/drm/i915/display/intel_cx0_phy.c
>> @@ -224,7 +224,8 @@ static int __intel_cx0_read_once(struct intel_encoder
>> *encoder,
>>  	 * down and let the message bus to end up
>>  	 * in a known state
>>  	 */
>> -	intel_cx0_bus_reset(encoder, lane);
>> +	if ((DISPLAY_VER(i915) >= 30))
>> +		intel_cx0_bus_reset(encoder, lane);
>> 
>>  	return REG_FIELD_GET(XELPDP_PORT_P2M_DATA_MASK, val);  } @@ -
>> 313,7 +314,8 @@ static int __intel_cx0_write_once(struct intel_encoder
>> *encoder,
>>  	 * down and let the message bus to end up
>>  	 * in a known state
>>  	 */
>> -	intel_cx0_bus_reset(encoder, lane);
>> +	if ((DISPLAY_VER(i915) >= 30))
>> +		intel_cx0_bus_reset(encoder, lane);
>> 
>>  	return 0;
>>  }
>> --
>> 2.25.1
>

-- 
Jani Nikula, Intel