On 3 October 2016 at 06:39, Alexandre Courbot <gnurou@xxxxxxxxx> wrote: > 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. OK, will do that. _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
