[PATCH] drm/amdgpu/display: add quirk handling for stutter mode

[Alex Deucher]

Stutter mode is a power saving feature on GPUs, however at
least one early raven system exhibits stability issues with
it.  Add a quirk to disable it for that system.

Bug: https://bugzilla.kernel.org/show_bug.cgi?id=214417
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
 .../gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 33 +++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index 5b8d1635da5c..b635b893837b 100644
--- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -1295,6 +1295,37 @@ static struct hpd_rx_irq_offload_work_queue *hpd_rx_irq_create_workqueue(struct
 	return hpd_rx_offload_wq;
 }
 
+struct amdgpu_stutter_quirk {
+	u16 chip_vendor;
+	u16 chip_device;
+	u16 subsys_vendor;
+	u16 subsys_device;
+	u8 revision;
+};
+
+static const struct amdgpu_stutter_quirk amdgpu_stutter_quirk_list[] = {
+	/* https://bugzilla.kernel.org/show_bug.cgi?id=214417 */
+	{ 0x1002, 0x15dd, 0x1002, 0x15dd, 0xc8 },
+	{ 0, 0, 0, 0, 0 },
+};
+
+static bool dm_should_disable_stutter(struct pci_dev *pdev)
+{
+	const struct amdgpu_stutter_quirk *p = amdgpu_stutter_quirk_list;
+
+	while (p && p->chip_device != 0) {
+		if (pdev->vendor == p->chip_vendor &&
+		    pdev->device == p->chip_device &&
+		    pdev->subsystem_vendor == p->subsys_vendor &&
+		    pdev->subsystem_device == p->subsys_device &&
+		    pdev->revision == p->revision) {
+			return true;
+		}
+		++p;
+	}
+	return false;
+}
+
 static int amdgpu_dm_init(struct amdgpu_device *adev)
 {
 	struct dc_init_data init_data;
@@ -1406,6 +1437,8 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
 
 	if (adev->asic_type != CHIP_CARRIZO && adev->asic_type != CHIP_STONEY)
 		adev->dm.dc->debug.disable_stutter = amdgpu_pp_feature_mask & PP_STUTTER_MODE ? false : true;
+	if (dm_should_disable_stutter(adev->pdev))
+		adev->dm.dc->debug.disable_stutter = true;
 
 	if (amdgpu_dc_debug_mask & DC_DISABLE_STUTTER)
 		adev->dm.dc->debug.disable_stutter = true;
-- 
2.31.1