On Mon, Aug 11, 2025 at 5:57 PM James Jones <jajo...@nvidia.com> wrote: > > This series adds new format modifiers for 8 and 16-bit formats on GB20x > GPUs, preventing them from mistakenly sharing block-linear surfaces > using these formats with prior GPUs that use a different layout. > > There are a few ways the parameteric format modifier definition > could have been altered to handle the new layouts: > > -The GOB Height and Page Kind field has a reserved value that could > have been used. However, the GOB height and page kind enums did > not change relative to prior chips, so this is sort of a lie. > However, this is the least-invasive change. > > -An entirely new field could have been added. This seems > inappropriate given the presence of an existing appropriate field. > The advantage here is it avoids splitting the sector layout field > across two bitfields. > > The chosen approach is the logically consistent one, but has the > downside of being the most complex, and that it causes the > DRM_FORMAT_MOD_NVIDIA_BLOCK_LINEAR_2D() macro to evaluate its 's' > parameter twice. However, utilizing simple helper functions in > client code when accessing the parameteric format modifier fields > easily addresses the complexity, and I have audited the relevant code > and do not believe the double evaluation should cause any problems in > practice. > > Tested on GB20x and TU10x cards using the following: > > -kmscube w/NVK+Zink built with these patches applied: > > https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/36336
Both the Mesa and kernel pieces are now reviewed so I think we're good to start landing. I've independently tested with kmscube to verify. ~Faith > > with various manually specified formats > and both manually specified and automatically > selected modifiers. > > -drmfmtmods, a tiny test program that lists modifiers: > > https://github.com/cubanismo/drmfmtmods > > Changes since the RFC version here: > > https://lore.kernel.org/nouveau/20250703223658.1457-1-jajo...@nvidia.com/ > > -Dropped the helper macros & static inlines in > drm_fourcc.h as requested by Faith Ekstrand, > who noted these aren't helpful for UMD code, > which is all written in rust now. I may re- > introduce some of these in a subsequent series, > but we both agreed we do not want to delay > progress on the modifiers themselves while we > debate the details of those cometic details. > > -Reserved an extra bit for future sector > layouts. > > -Fixed handling of linear modifiers on GB20x > and NV5x/G8x/G9x/GT2xx chips. > > James Jones (3): > drm: define NVIDIA DRM format modifiers for GB20x > drm/nouveau/disp: Always accept linear modifier > drm/nouveau: Advertise correct modifiers on GB20x > > drivers/gpu/drm/nouveau/dispnv50/disp.c | 3 ++ > drivers/gpu/drm/nouveau/dispnv50/disp.h | 1 + > drivers/gpu/drm/nouveau/dispnv50/wndw.c | 25 ++++++++++++++-- > drivers/gpu/drm/nouveau/dispnv50/wndwca7e.c | 33 +++++++++++++++++++++ > include/uapi/drm/drm_fourcc.h | 25 ++++++++++------ > 5 files changed, 76 insertions(+), 11 deletions(-) > > -- > 2.50.1 >
