Re: [PATCH] drm/amd/pm: conditionally disable pcie lane switching for some sienna_cichlid SKUs

["Lazar, Lijo" <lijo.lazar@xxxxxxx>]

On 4/21/2023 1:02 PM, Quan, Evan wrote:
> [AMD Official Use Only - General]
>
> This seems able to address some audio noise issue observed per customer's feedback.
>
> Evan
> > -----Original Message-----
> > From: Quan, Evan <Evan.Quan@xxxxxxx>
> > Sent: Friday, April 21, 2023 3:29 PM
> > To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
> > Cc: Deucher, Alexander <Alexander.Deucher@xxxxxxx>; Limonciello, Mario
> > <Mario.Limonciello@xxxxxxx>; Quan, Evan <Evan.Quan@xxxxxxx>
> > Subject: [PATCH] drm/amd/pm: conditionally disable pcie lane switching for
> > some sienna_cichlid SKUs
> >
> > Disable the pcie lane switching for some sienna_cichlid SKUs since it
> > might not work well on some platforms.
> >
> > Signed-off-by: Evan Quan <evan.quan@xxxxxxx>
> > Change-Id: Iea9ceaa146c8706768ee077c10e5d33bce9bc1c2
> > ---
> >   .../amd/pm/swsmu/smu11/sienna_cichlid_ppt.c   | 92 +++++++++++++++---
> > -
> >   1 file changed, 74 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c
> > b/drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c
> > index 4b91cdc3eaa0..e7223513e384 100644
> > --- a/drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c
> > +++ b/drivers/gpu/drm/amd/pm/swsmu/smu11/sienna_cichlid_ppt.c
> > @@ -2067,33 +2067,94 @@ static int
> > sienna_cichlid_display_disable_memory_clock_switch(struct smu_context
> >   	return ret;
> >   }
> >
> > +static void sienna_cichlid_get_override_pcie_settings(struct smu_context
> > *smu,
> > +						      uint32_t
> > *gen_speed_override,
> > +						      uint32_t
> > *lane_width_override)
> > +{
> > +	struct amdgpu_device *adev = smu->adev;
> > +
> > +	*gen_speed_override = 0xff;
> > +	*lane_width_override = 0xff;
> > +
> > +	switch (adev->pdev->device) {
> > +	case 0x73A0:
> > +	case 0x73A1:
> > +	case 0x73A2:
> > +	case 0x73A3:
> > +	case 0x73AB:
> > +	case 0x73AE:
> > +		/* Bit 7:0: PCIE lane width, 1 to 7 corresponds is x1 to x32 */
> > +		*lane_width_override = 6;
> > +		break;
> > +	case 0x73E0:
> > +	case 0x73E1:
> > +	case 0x73E3:
> > +		*lane_width_override = 4;
> > +		break;
> > +	case 0x7420:
> > +	case 0x7421:
> > +	case 0x7422:
> > +	case 0x7423:
> > +	case 0x7424:
> > +		*lane_width_override = 3;
> > +		break;
> > +	default:
> > +		break;
> > +	}
> > +}
> > +

Isn't this applicable only on Intel platforms? If so, better to do a 
processor check rather than maintaining max width based on DID.

Thanks,
Lijo

> > +#define MAX(a, b)	((a) > (b) ? (a) : (b))
> > +
> >   static int sienna_cichlid_update_pcie_parameters(struct smu_context *smu,
> >   					 uint32_t pcie_gen_cap,
> >   					 uint32_t pcie_width_cap)
> >   {
> >   	struct smu_11_0_dpm_context *dpm_context = smu-
> > > smu_dpm.dpm_context;
> > -
> > -	uint32_t smu_pcie_arg;
> > +	struct smu_11_0_pcie_table *pcie_table = &dpm_context-
> > > dpm_tables.pcie_table;
> > +	uint32_t gen_speed_override, lane_width_override;
> >   	uint8_t *table_member1, *table_member2;
> > +	uint32_t min_gen_speed, max_gen_speed;
> > +	uint32_t min_lane_width, max_lane_width;
> > +	uint32_t smu_pcie_arg;
> >   	int ret, i;
> >
> >   	GET_PPTABLE_MEMBER(PcieGenSpeed, &table_member1);
> >   	GET_PPTABLE_MEMBER(PcieLaneCount, &table_member2);
> >
> > -	/* lclk dpm table setup */
> > -	for (i = 0; i < MAX_PCIE_CONF; i++) {
> > -		dpm_context->dpm_tables.pcie_table.pcie_gen[i] =
> > table_member1[i];
> > -		dpm_context->dpm_tables.pcie_table.pcie_lane[i] =
> > table_member2[i];
> > +	sienna_cichlid_get_override_pcie_settings(smu,
> > +						  &gen_speed_override,
> > +						  &lane_width_override);
> > +
> > +	/* PCIE gen speed override */
> > +	if (gen_speed_override != 0xff) {
> > +		min_gen_speed = MIN(pcie_gen_cap, gen_speed_override);
> > +		max_gen_speed = MIN(pcie_gen_cap,
> > gen_speed_override);
> > +	} else {
> > +		min_gen_speed = MAX(0, table_member1[0]);
> > +		max_gen_speed = MIN(pcie_gen_cap, table_member1[1]);
> > +		min_gen_speed = min_gen_speed > max_gen_speed ?
> > +				max_gen_speed : min_gen_speed;
> >   	}
> > +	pcie_table->pcie_gen[0] = min_gen_speed;
> > +	pcie_table->pcie_gen[1] = max_gen_speed;
> > +
> > +	/* PCIE lane width override */
> > +	if (lane_width_override != 0xff) {
> > +		min_lane_width = MIN(pcie_width_cap,
> > lane_width_override);
> > +		max_lane_width = MIN(pcie_width_cap,
> > lane_width_override);
> > +	} else {
> > +		min_lane_width = MAX(1, table_member2[0]);
> > +		max_lane_width = MIN(pcie_width_cap, table_member2[1]);
> > +		min_lane_width = min_lane_width > max_lane_width ?
> > +				 max_lane_width : min_lane_width;
> > +	}
> > +	pcie_table->pcie_lane[0] = min_lane_width;
> > +	pcie_table->pcie_lane[1] = max_lane_width;
> >
> >   	for (i = 0; i < NUM_LINK_LEVELS; i++) {
> > -		smu_pcie_arg = (i << 16) |
> > -			((table_member1[i] <= pcie_gen_cap) ?
> > -			 (table_member1[i] << 8) :
> > -			 (pcie_gen_cap << 8)) |
> > -			((table_member2[i] <= pcie_width_cap) ?
> > -			 table_member2[i] :
> > -			 pcie_width_cap);
> > +		smu_pcie_arg = (i << 16 |
> > +				pcie_table->pcie_gen[i] << 8 |
> > +				pcie_table->pcie_lane[i]);
> >
> >   		ret = smu_cmn_send_smc_msg_with_param(smu,
> >   				SMU_MSG_OverridePcieParameters,
> > @@ -2101,11 +2162,6 @@ static int
> > sienna_cichlid_update_pcie_parameters(struct smu_context *smu,
> >   				NULL);
> >   		if (ret)
> >   			return ret;
> > -
> > -		if (table_member1[i] > pcie_gen_cap)
> > -			dpm_context->dpm_tables.pcie_table.pcie_gen[i] =
> > pcie_gen_cap;
> > -		if (table_member2[i] > pcie_width_cap)
> > -			dpm_context->dpm_tables.pcie_table.pcie_lane[i] =
> > pcie_width_cap;
> >   	}
> >
> >   	return 0;
> > --
> > 2.34.1