On Mon, Sep 26, 2016 at 9:32 PM, Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote: > Some subdevices (i.e., fb/nv50.c and fb/gf100.c) map a scratch page using > dma_map_page() way before the TTM layer has had a chance to set the DMA > mask. This may prevent the driver from loading at all on platforms whose > system memory is not covered by the default DMA mask of 32-bit (i.e., when > all RAM is above 4 GB). > > So set a preliminary DMA mask right after constructing the PCI device, and > base it on the .dma_bits member of the MMU subdevice, which is what the TTM > layer will base the DMA mask on as well. > > Signed-off-by: Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> > --- > drivers/gpu/drm/nouveau/nouveau_drm.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c > index 652ab111dd74..e61e9a0adb51 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_drm.c > +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c > @@ -361,6 +361,17 @@ static int nouveau_drm_probe(struct pci_dev *pdev, > > pci_set_master(pdev); > > + /* > + * Set a preliminary DMA mask based on the .dma_bits member of the > + * MMU subdevice. This allows other subdevices to create DMA mappings > + * in their init() function, which are called before the TTM layer sets > + * the DMA mask definitively. > + * This is necessary for platforms where the default DMA mask of 32 > + * does not cover any system memory, i.e., when all RAM is > 4 GB. > + */ > + dma_set_mask_and_coherent(device->dev, > + DMA_BIT_MASK(device->mmu->dma_bits)); I would just move this to nvkm_device_pci_new() so that it perfectly mirrors the same call done in nvkm_device_tegra_new(), which was done for the same purpose. Otherwise, looks good to me. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
