This reverts commit f295c8cfec833c2707ff1512da10d65386dde7af.

Starting with commit f295c8cfec833c2707ff1512da10d65386dde7af ("drm/nouveau: fix dma syncing warning with debugging on.") the following oops occures:

BUG: kernel NULL pointer dereference, address: 0000000000000000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 0 P4D 0 Oops: 0000 [#1] PREEMPT SMP PTI CPU: 6 PID: 1013 Comm: Xorg.bin Tainted: G E 5.11.0-desktop-rc0+ #2 Hardware name: Acer Aspire VN7-593G/Pluto_KLS, BIOS V1.11 08/01/2018 RIP: 0010:nouveau_bo_sync_for_device+0x40/0xb0 [nouveau] Call Trace: nouveau_bo_validate+0x5d/0x80 [nouveau] nouveau_gem_ioctl_pushbuf+0x662/0x1120 [nouveau] ? nouveau_gem_ioctl_new+0xf0/0xf0 [nouveau] drm_ioctl_kernel+0xa6/0xf0 [drm] drm_ioctl+0x1f4/0x3a0 [drm] ? nouveau_gem_ioctl_new+0xf0/0xf0 [nouveau] nouveau_drm_ioctl+0x50/0xa0 [nouveau] __x64_sys_ioctl+0x7e/0xb0 do_syscall_64+0x33/0x80 entry_SYSCALL_64_after_hwframe+0x44/0xae ---[ end trace ccfb1e7f4064374f ]--- RIP: 0010:nouveau_bo_sync_for_device+0x40/0xb0 [nouveau]

Reverting the commit, fixes the issue!

Signed-off-by: Tobias Klausmann tobias.klausmann@freenet.de --- drivers/gpu/drm/nouveau/nouveau_bo.c | 35 +++++----------------------- 1 file changed, 6 insertions(+), 29 deletions(-)

diff --git a/drivers/gpu/drm/nouveau/nouveau_bo.c b/drivers/gpu/drm/nouveau/nouveau_bo.c index 2375711877cf..33dc886d1d6d 100644 --- a/drivers/gpu/drm/nouveau/nouveau_bo.c +++ b/drivers/gpu/drm/nouveau/nouveau_bo.c @@ -547,7 +547,7 @@ nouveau_bo_sync_for_device(struct nouveau_bo *nvbo) { struct nouveau_drm *drm = nouveau_bdev(nvbo->bo.bdev); struct ttm_tt *ttm_dma = (struct ttm_tt *)nvbo->bo.ttm; - int i, j; + int i;

if (!ttm_dma) return; @@ -556,21 +556,10 @@ nouveau_bo_sync_for_device(struct nouveau_bo *nvbo) if (nvbo->force_coherent) return;

- for (i = 0; i < ttm_dma->num_pages; ++i) { - struct page *p = ttm_dma->pages[i]; - size_t num_pages = 1; - - for (j = i + 1; j < ttm_dma->num_pages; ++j) { - if (++p != ttm_dma->pages[j]) - break; - - ++num_pages; - } + for (i = 0; i < ttm_dma->num_pages; i++) dma_sync_single_for_device(drm->dev->dev, ttm_dma->dma_address[i], - num_pages * PAGE_SIZE, DMA_TO_DEVICE); - i += num_pages; - } + PAGE_SIZE, DMA_TO_DEVICE); }

void @@ -578,7 +567,7 @@ nouveau_bo_sync_for_cpu(struct nouveau_bo *nvbo) { struct nouveau_drm *drm = nouveau_bdev(nvbo->bo.bdev); struct ttm_tt *ttm_dma = (struct ttm_tt *)nvbo->bo.ttm; - int i, j; + int i;

if (!ttm_dma) return; @@ -587,21 +576,9 @@ nouveau_bo_sync_for_cpu(struct nouveau_bo *nvbo) if (nvbo->force_coherent) return;

- for (i = 0; i < ttm_dma->num_pages; ++i) { - struct page *p = ttm_dma->pages[i]; - size_t num_pages = 1; - - for (j = i + 1; j < ttm_dma->num_pages; ++j) { - if (++p != ttm_dma->pages[j]) - break; - - ++num_pages; - } - + for (i = 0; i < ttm_dma->num_pages; i++) dma_sync_single_for_cpu(drm->dev->dev, ttm_dma->dma_address[i], - num_pages * PAGE_SIZE, DMA_FROM_DEVICE); - i += num_pages; - } + PAGE_SIZE, DMA_FROM_DEVICE); }

void nouveau_bo_add_io_reserve_lru(struct ttm_buffer_object *bo)