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[RFC] drm/nouveau/ttm: Stop calling into swiotlb

Message ID 20220728220545.163763-1-lyude@redhat.com (mailing list archive)
State New, archived
Headers show
Series [RFC] drm/nouveau/ttm: Stop calling into swiotlb | expand

Commit Message

Lyude Paul July 28, 2022, 10:05 p.m. UTC
Per the request of some of the DMA folks, some of the swiotlb helpers are
being sunset in favor of better alternatives that don't involve layer
mixing. Since it seems like we can actually replace the one thing we use
swiotlb for pretty easily, e.g. checking whether or not we are capable of
coherent allocations using is_swiotlb_active().

So, let's do this by replacing is_swiotlb_active() with our own
nouveau_drm_use_coherent_gpu_mapping() helper.

Signed-off-by: Lyude Paul <lyude@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
---

Hey! This is the patch that I came up with, but as the folks involved
with this thread can probably tell I'm not entirely sure this is
correct?

Also, someone more knowledgeable about mm with nouveau should probably
verify this as well

 drivers/gpu/drm/nouveau/nouveau_ttm.c | 13 ++++---------
 1 file changed, 4 insertions(+), 9 deletions(-)
diff mbox series

Patch

diff --git a/drivers/gpu/drm/nouveau/nouveau_ttm.c b/drivers/gpu/drm/nouveau/nouveau_ttm.c
index 85f1f5a0fe5d..ab7ccba1d601 100644
--- a/drivers/gpu/drm/nouveau/nouveau_ttm.c
+++ b/drivers/gpu/drm/nouveau/nouveau_ttm.c
@@ -24,7 +24,6 @@ 
  */
 
 #include <linux/limits.h>
-#include <linux/swiotlb.h>
 
 #include <drm/ttm/ttm_range_manager.h>
 
@@ -241,7 +240,6 @@  nouveau_ttm_init(struct nouveau_drm *drm)
 	struct nvkm_pci *pci = device->pci;
 	struct nvif_mmu *mmu = &drm->client.mmu;
 	struct drm_device *dev = drm->dev;
-	bool need_swiotlb = false;
 	int typei, ret;
 
 	ret = nouveau_ttm_init_host(drm, 0);
@@ -276,14 +274,11 @@  nouveau_ttm_init(struct nouveau_drm *drm)
 		drm->agp.cma = pci->agp.cma;
 	}
 
-#if IS_ENABLED(CONFIG_SWIOTLB) && IS_ENABLED(CONFIG_X86)
-	need_swiotlb = is_swiotlb_active(dev->dev);
-#endif
-
 	ret = ttm_device_init(&drm->ttm.bdev, &nouveau_bo_driver, drm->dev->dev,
-				  dev->anon_inode->i_mapping,
-				  dev->vma_offset_manager, need_swiotlb,
-				  drm->client.mmu.dmabits <= 32);
+			      dev->anon_inode->i_mapping,
+			      dev->vma_offset_manager,
+			      nouveau_drm_use_coherent_gpu_mapping(drm),
+			      drm->client.mmu.dmabits <= 32);
 	if (ret) {
 		NV_ERROR(drm, "error initialising bo driver, %d\n", ret);
 		return ret;