drm/nouveau: Revert "bus: remove cpu_coherent flag"

This reverts commit aff51175cdbf345740ec9203eff88e772af88059.

The commit caused fence timeouts within nvc0_screen_destroy and most likely
other places as well.

The most obvious effect is, that userspace processes take minutes to
actually quit.

Signed-off-by: Karol Herbst <karolherbst@gmail.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

4 files changed, 5 insertions, 1 deletions

diff --git a/drivers/gpu/drm/nouveau/include/nvkm/core/device.h b/drivers/gpu/drm/nouveau/include/nvkm/core/device.h
index 7ea8aa7ca408..6bc712f32c8b 100644
--- a/drivers/gpu/drm/nouveau/include/nvkm/core/device.h
+++ b/drivers/gpu/drm/nouveau/include/nvkm/core/device.h
@@ -175,6 +175,7 @@ struct nvkm_device_func {
         void (*fini)(struct nvkm_device *, bool suspend);
         resource_size_t (*resource_addr)(struct nvkm_device *, unsigned bar);
         resource_size_t (*resource_size)(struct nvkm_device *, unsigned bar);
+        bool cpu_coherent;
 };
 
 struct nvkm_device_quirk {
diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c
index 6190035edfea..864323b19cf7 100644
--- a/drivers/gpu/drm/nouveau/nouveau_bo.c
+++ b/drivers/gpu/drm/nouveau/nouveau_bo.c
@@ -209,7 +209,8 @@ nouveau_bo_new(struct drm_device *dev, int size, int align,
         nvbo->tile_flags = tile_flags;
         nvbo->bo.bdev = &drm->ttm.bdev;
 
-        nvbo->force_coherent = flags & TTM_PL_FLAG_UNCACHED;
+        if (!nvxx_device(&drm->device)->func->cpu_coherent)
+                nvbo->force_coherent = flags & TTM_PL_FLAG_UNCACHED;
 
         nvbo->page_shift = 12;
         if (drm->client.vm) {
diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/pci.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/pci.c
index b1b693219db3..62ad0300cfa5 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/device/pci.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/pci.c
@@ -1614,6 +1614,7 @@ nvkm_device_pci_func = {
         .fini = nvkm_device_pci_fini,
         .resource_addr = nvkm_device_pci_resource_addr,
         .resource_size = nvkm_device_pci_resource_size,
+        .cpu_coherent = !IS_ENABLED(CONFIG_ARM),
 };
 
 int
diff --git a/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c b/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c
index 939682f18788..9b638bd905ff 100644
--- a/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c
+++ b/drivers/gpu/drm/nouveau/nvkm/engine/device/tegra.c
@@ -245,6 +245,7 @@ nvkm_device_tegra_func = {
         .fini = nvkm_device_tegra_fini,
         .resource_addr = nvkm_device_tegra_resource_addr,
         .resource_size = nvkm_device_tegra_resource_size,
+        .cpu_coherent = false,
 };
 
 int