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

[Lazar, Lijo]

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.q...@amd.com>
Sent: Friday, April 21, 2023 3:29 PM
To: amd-gfx@lists.freedesktop.org
Cc: Deucher, Alexander <alexander.deuc...@amd.com>; Limonciello, Mario
<mario.limoncie...@amd.com>; Quan, Evan <evan.q...@amd.com>
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.q...@amd.com>
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