[PATCH V4 1/1] drm/amdgpu: Disable PCIE_DPM on Intel RKL Platform

[Koba Ko]

Due to high latency in PCIE clock switching on RKL platforms,
switching the PCIE clock dynamically at runtime can lead to HDMI/DP
audio problems. On newer asics this is handled in the SMU firmware.
For SMU7-based asics, disable PCIE clock switching to avoid the issue.

AMD provide a parameter to disable PICE_DPM.

modprobe amdgpu ppfeaturemask=0xfff7bffb

It's better to contorl PCIE_DPM in amd gpu driver,
switch PCI_DPM by determining intel RKL platform for SMU7-based asics.

Fixes: 1a31474cdb48 ("drm/amd/pm: workaround for audio noise issue")
Ref: https://lists.freedesktop.org/archives/amd-gfx/2021-August/067413.html
Signed-off-by: Koba Ko <koba.ko at canonical.com>
---
 .../gpu/drm/amd/pm/powerplay/hwmgr/smu7_hwmgr.c | 17 ++++++++++++++++-
 1 file changed, 16 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_hwmgr.c b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_hwmgr.c
index 0541bfc81c1b..1d76cf7cd85d 100644
--- a/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_hwmgr.c
+++ b/drivers/gpu/drm/amd/pm/powerplay/hwmgr/smu7_hwmgr.c
@@ -27,6 +27,9 @@
 #include <linux/pci.h>
 #include <linux/slab.h>
 #include <asm/div64.h>
+#if IS_ENABLED(CONFIG_X86_64)
+#include <asm/intel-family.h>
+#endif
 #include <drm/amdgpu_drm.h>
 #include "ppatomctrl.h"
 #include "atombios.h"
@@ -1733,6 +1736,17 @@ static int smu7_disable_dpm_tasks(struct pp_hwmgr *hwmgr)
 	return result;
 }
 
+static bool intel_core_rkl_chk(void)
+{
+#if IS_ENABLED(CONFIG_X86_64)
+	struct cpuinfo_x86 *c = &cpu_data(0);
+
+	return (c->x86 == 6 && c->x86_model == INTEL_FAM6_ROCKETLAKE);
+#else
+	return false;
+#endif
+}
+
 static void smu7_init_dpm_defaults(struct pp_hwmgr *hwmgr)
 {
 	struct smu7_hwmgr *data = (struct smu7_hwmgr *)(hwmgr->backend);
@@ -1758,7 +1772,8 @@ static void smu7_init_dpm_defaults(struct pp_hwmgr *hwmgr)
 
 	data->mclk_dpm_key_disabled = hwmgr->feature_mask & PP_MCLK_DPM_MASK ? false : true;
 	data->sclk_dpm_key_disabled = hwmgr->feature_mask & PP_SCLK_DPM_MASK ? false : true;
-	data->pcie_dpm_key_disabled = hwmgr->feature_mask & PP_PCIE_DPM_MASK ? false : true;
+	data->pcie_dpm_key_disabled =
+		intel_core_rkl_chk() || !(hwmgr->feature_mask & PP_PCIE_DPM_MASK);
 	/* need to set voltage control types before EVV patching */
 	data->voltage_control = SMU7_VOLTAGE_CONTROL_NONE;
 	data->vddci_control = SMU7_VOLTAGE_CONTROL_NONE;
-- 
2.25.1