[Nouveau] [PATCH v4 3/4] pci: set the pcie link speed to 8.0 when suspending

[Karol Herbst]

Apperantly things go south if we suspend the device with a PCIe link speed
set to 2.5. Fixes runtime suspend on my gp107.

This all looks like some bug inside the pci subsystem and I would prefer a
fix there instead of nouveau, but maybe there is no real nice way of doing
that outside of drivers?

v2: squashed together patch 4 and 5
v3: only restore pcie speed on machines with runpm
    add NvRunpmWorkaround config option to disable the workaround
v4: only run the code on suspend
    always put the card into 8.0 mode, not what nouveau detected on load

Signed-off-by: Karol Herbst <kherbst at redhat.com>
Reviewed-by: Lyude Paul <lyude at redhat.com> (v2)
---
 drm/nouveau/include/nvkm/core/device.h |  2 ++
 drm/nouveau/include/nvkm/subdev/pci.h  |  3 ++-
 drm/nouveau/nouveau_drm.c              |  1 +
 drm/nouveau/nvkm/subdev/clk/base.c     |  2 +-
 drm/nouveau/nvkm/subdev/pci/base.c     |  2 ++
 drm/nouveau/nvkm/subdev/pci/pcie.c     | 27 ++++++++++++++++++++++----
 drm/nouveau/nvkm/subdev/pci/priv.h     |  1 +
 7 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/drm/nouveau/include/nvkm/core/device.h b/drm/nouveau/include/nvkm/core/device.h
index 6d55cd047..4fb3f972f 100644
--- a/drm/nouveau/include/nvkm/core/device.h
+++ b/drm/nouveau/include/nvkm/core/device.h
@@ -125,6 +125,8 @@ struct nvkm_device {
 	u8  chiprev;
 	u32 crystal;
 
+	bool has_runpm;
+
 	struct {
 		struct notifier_block nb;
 	} acpi;
diff --git a/drm/nouveau/include/nvkm/subdev/pci.h b/drm/nouveau/include/nvkm/subdev/pci.h
index b29101e48..7245513d9 100644
--- a/drm/nouveau/include/nvkm/subdev/pci.h
+++ b/drm/nouveau/include/nvkm/subdev/pci.h
@@ -52,6 +52,7 @@ int gk104_pci_new(struct nvkm_device *, int, struct nvkm_pci **);
 int gp100_pci_new(struct nvkm_device *, int, struct nvkm_pci **);
 
 /* pcie functions */
-int nvkm_pcie_set_link(struct nvkm_pci *, enum nvkm_pcie_speed, u8 width);
+int nvkm_pcie_set_link(struct nvkm_pci *, enum nvkm_pcie_speed, u8 width,
+		       bool save);
 enum nvkm_pcie_speed nvkm_pcie_get_speed(struct nvkm_pci *);
 #endif
diff --git a/drm/nouveau/nouveau_drm.c b/drm/nouveau/nouveau_drm.c
index 3d32afe8a..78d55c525 100644
--- a/drm/nouveau/nouveau_drm.c
+++ b/drm/nouveau/nouveau_drm.c
@@ -676,6 +676,7 @@ static int nouveau_drm_probe(struct pci_dev *pdev,
 
 	if (nouveau_atomic)
 		driver_pci.driver_features |= DRIVER_ATOMIC;
+	device->has_runpm = nouveau_pmops_runtime();
 
 	drm_dev = drm_dev_alloc(&driver_pci, &pdev->dev);
 	if (IS_ERR(drm_dev)) {
diff --git a/drm/nouveau/nvkm/subdev/clk/base.c b/drm/nouveau/nvkm/subdev/clk/base.c
index ba6a868d4..e30e77453 100644
--- a/drm/nouveau/nvkm/subdev/clk/base.c
+++ b/drm/nouveau/nvkm/subdev/clk/base.c
@@ -277,7 +277,7 @@ nvkm_pstate_prog(struct nvkm_clk *clk, int pstatei)
 	nvkm_debug(subdev, "setting performance state %d\n", pstatei);
 	clk->pstate = pstatei;
 
-	nvkm_pcie_set_link(pci, pstate->pcie_speed, pstate->pcie_width);
+	nvkm_pcie_set_link(pci, pstate->pcie_speed, pstate->pcie_width, true);
 
 	if (fb && fb->ram && fb->ram->func->calc) {
 		struct nvkm_ram *ram = fb->ram;
diff --git a/drm/nouveau/nvkm/subdev/pci/base.c b/drm/nouveau/nvkm/subdev/pci/base.c
index ee2431a78..c9b60ef76 100644
--- a/drm/nouveau/nvkm/subdev/pci/base.c
+++ b/drm/nouveau/nvkm/subdev/pci/base.c
@@ -90,6 +90,8 @@ nvkm_pci_fini(struct nvkm_subdev *subdev, bool suspend)
 
 	if (pci->agp.bridge)
 		nvkm_agp_fini(pci);
+	else if (pci_is_pcie(pci->pdev))
+		nvkm_pcie_fini(pci, suspend);
 
 	return 0;
 }
diff --git a/drm/nouveau/nvkm/subdev/pci/pcie.c b/drm/nouveau/nvkm/subdev/pci/pcie.c
index b4203ff1a..5cab4a240 100644
--- a/drm/nouveau/nvkm/subdev/pci/pcie.c
+++ b/drm/nouveau/nvkm/subdev/pci/pcie.c
@@ -23,6 +23,8 @@
  */
 #include "priv.h"
 
+#include <core/option.h>
+
 static char *nvkm_pcie_speeds[] = {
 	"2.5GT/s",
 	"5.0GT/s",
@@ -106,11 +108,25 @@ nvkm_pcie_init(struct nvkm_pci *pci)
 		pci->func->pcie.init(pci);
 
 	if (pci->pcie.speed != -1)
-		nvkm_pcie_set_link(pci, pci->pcie.speed, pci->pcie.width);
+		nvkm_pcie_set_link(pci, pci->pcie.speed,
+				   pci->pcie.width, false);
 
 	return 0;
 }
 
+int
+nvkm_pcie_fini(struct nvkm_pci *pci, bool suspend)
+{
+	struct nvkm_device *device = pci->subdev.device;
+	if (!device->has_runpm || !suspend)
+		return 0;
+
+	if (!nvkm_boolopt(device->cfgopt, "NvRunpmWorkaround", true))
+		return 0;
+
+	return nvkm_pcie_set_link(pci, NVKM_PCIE_SPEED_8_0, 16, false);
+}
+
 void
 nvkm_pcie_force_aspm_off(struct nvkm_pci *pci, bool status)
 {
@@ -120,7 +136,8 @@ nvkm_pcie_force_aspm_off(struct nvkm_pci *pci, bool status)
 }
 
 int
-nvkm_pcie_set_link(struct nvkm_pci *pci, enum nvkm_pcie_speed speed, u8 width)
+nvkm_pcie_set_link(struct nvkm_pci *pci, enum nvkm_pcie_speed speed, u8 width,
+                   bool save)
 {
 	struct nvkm_subdev *subdev = &pci->subdev;
 	enum nvkm_pcie_speed cur_speed, max_speed;
@@ -154,8 +171,10 @@ nvkm_pcie_set_link(struct nvkm_pci *pci, enum nvkm_pcie_speed speed, u8 width)
 		speed = max_speed;
 	}
 
-	pci->pcie.speed = speed;
-	pci->pcie.width = width;
+	if (save) {
+		pci->pcie.speed = speed;
+		pci->pcie.width = width;
+	}
 
 	if (speed == cur_speed) {
 		nvkm_debug(subdev, "requested matches current speed\n");
diff --git a/drm/nouveau/nvkm/subdev/pci/priv.h b/drm/nouveau/nvkm/subdev/pci/priv.h
index 82c78befa..6bea37c15 100644
--- a/drm/nouveau/nvkm/subdev/pci/priv.h
+++ b/drm/nouveau/nvkm/subdev/pci/priv.h
@@ -63,4 +63,5 @@ int gk104_pcie_version_supported(struct nvkm_pci *);
 
 int nvkm_pcie_oneinit(struct nvkm_pci *);
 int nvkm_pcie_init(struct nvkm_pci *);
+int nvkm_pcie_fini(struct nvkm_pci *, bool suspend);
 #endif
-- 
2.21.0