While Kepler does technically support 256x256 cursors, it turns out that in order for us to use these correctly we need to make sure that the cursor plane uses a ctxdma that is set to use small (4K)/large (128K) pages - whichever is applicable to the given cursor surface.

Right now however, we share the main kmsVramCtxDma that is used for all but the ovly plane which defaults to small pages - resulting in artifacts when we use 256x256 cursor surfaces. So until we teach nouveau to use a separate ctxdma for the cursor, let's just stop advertising 256x256 cursors by default - which should fix the issues that users were seeing.

Coincidentally - this is also why small ovlys don't work on Kepler: the ctxdma we use for ovlys is set to large pages.

Changes since v2: * Fix comments and patch description

Signed-off-by: Lyude Paul lyude@redhat.com Fixes: d3b2f0f7921c ("drm/nouveau/kms/nv50-: Report max cursor size to userspace") Cc: stable@vger.kernel.org # v5.11+ --- drivers/gpu/drm/nouveau/dispnv50/disp.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/nouveau/dispnv50/disp.c b/drivers/gpu/drm/nouveau/dispnv50/disp.c index 196612addfd6..d92cf9e17ac3 100644 --- a/drivers/gpu/drm/nouveau/dispnv50/disp.c +++ b/drivers/gpu/drm/nouveau/dispnv50/disp.c @@ -2693,9 +2693,19 @@ nv50_display_create(struct drm_device *dev) else nouveau_display(dev)->format_modifiers = disp50xx_modifiers;

- if (disp->disp->object.oclass >= GK104_DISP) { + /* FIXME: 256x256 cursors are supported on Kepler, however unlike Maxwell and later + * generations Kepler requires that we specify the page type, small (4K) or large (128K), + * correctly for the ctxdma being used on curs/ovly. We currently share a ctxdma across all + * display planes (except ovly) that defaults to small pages, which results in artifacting + * on 256x256 cursors. Until we teach nouveau to create an appropriate ctxdma for the cursor + * fb in use, simply avoid advertising support for 256x256 cursors. + */ + if (disp->disp->object.oclass >= GM107_DISP) { dev->mode_config.cursor_width = 256; dev->mode_config.cursor_height = 256; + } else if (disp->disp->object.oclass >= GK104_DISP) { + dev->mode_config.cursor_width = 128; + dev->mode_config.cursor_height = 128; } else { dev->mode_config.cursor_width = 64; dev->mode_config.cursor_height = 64;