On Fri, Jan 30, 2015 at 05:08:23PM +0100, Daniel Vetter wrote: > From: Rob Clark <robdclark@xxxxxxxxx> > > In DRM/KMS we are lacking a good way to deal with tiled/compressed > formats. Especially in the case of dmabuf/prime buffer sharing, where > we cannot always rely on under-the-hood flags passed to driver specific > gem-create ioctl to pass around these extra flags. > > The proposal is to add a per-plane format modifier. This allows to, if > necessary, use different tiling patters for sub-sampled planes, etc. "patterns". Alternatively perhaps "modes", which is how I've heard it referred to most commonly. > The format modifiers are added at the end of the ioctl struct, so for > legacy userspace it will be zero padded. > > v1: original > v1.5: increase modifier to 64b > > v2: Incorporate review comments from the big thread, plus a few more. > > - Add a getcap so that userspace doesn't have to jump through hoops. > - Allow modifiers only when a flag is set. That way drivers know when > they're dealing with old userspace and need to fish out e.g. tiling > from other information. > - After rolling out checks for ->modifier to all drivers I've decided > that this is way too fragile and needs an explicit opt-in flag. So > do that instead. > - Add a define (just for documentation really) for the "NONE" > modifier. Imo we don't need to add mask #defines since drivers > really should only do exact matches against values defined with > fourcc_mod_code. > - Drop the Samsung tiling modifier on Rob's request since he's not yet > sure whether that one is accurate. > > v3: > - Also add a new ->modifier[] array to struct drm_framebuffer and fill > it in drm_helper_mode_fill_fb_struct. Requested by Tvrtko Uruslin. > - Remove TODO in comment and add code comment that modifiers should be > properly documented, requested by Rob. > > v4: Balance parens, spotted by Tvrtko. > > Cc: Rob Clark <robdclark@xxxxxxxxx> > Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxxxxxxxx> > Cc: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> > Cc: Daniel Stone <daniel@xxxxxxxxxxxxx> > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Cc: Michel Dänzer <michel@xxxxxxxxxxx> > Signed-off-by: Rob Clark <robdclark@xxxxxxxxx> (v1.5) > Reviewed-by: Rob Clark <robdclark@xxxxxxxxx> > Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxxx> > --- > drivers/gpu/drm/drm_crtc.c | 14 +++++++++++++- > drivers/gpu/drm/drm_crtc_helper.c | 1 + > drivers/gpu/drm/drm_ioctl.c | 3 +++ > include/drm/drm_crtc.h | 4 ++++ > include/uapi/drm/drm.h | 1 + > include/uapi/drm/drm_fourcc.h | 32 ++++++++++++++++++++++++++++++++ > include/uapi/drm/drm_mode.h | 9 +++++++++ > 7 files changed, 63 insertions(+), 1 deletion(-) Also as discussed on IRC, I think this would be better in a non-DRM specific header so that we can have a central, cross-subsystem authority. > diff --git a/include/uapi/drm/drm_fourcc.h b/include/uapi/drm/drm_fourcc.h > index 646ae5f39f42..622109677747 100644 > --- a/include/uapi/drm/drm_fourcc.h > +++ b/include/uapi/drm/drm_fourcc.h > @@ -132,4 +132,36 @@ > #define DRM_FORMAT_YUV444 fourcc_code('Y', 'U', '2', '4') /* non-subsampled Cb (1) and Cr (2) planes */ > #define DRM_FORMAT_YVU444 fourcc_code('Y', 'V', '2', '4') /* non-subsampled Cr (1) and Cb (2) planes */ > > + Possibly unintented extra blank line? > +/* > + * Format Modifiers: > + * > + * Format modifiers describe, typically, a re-ordering or modification > + * of the data in a plane of an FB. This can be used to express tiled/ > + * swizzled formats, or compression, or a combination of the two. > + * > + * The upper 8 bits of the format modifier are a vendor-id as assigned > + * below. The lower 56 bits are assigned as vendor sees fit. > + */ > + > +/* Vendor Ids: */ > +#define DRM_FORMAT_MOD_NONE 0 > +#define DRM_FORMAT_MOD_VENDOR_INTEL 0x01 > +#define DRM_FORMAT_MOD_VENDOR_AMD 0x02 > +#define DRM_FORMAT_MOD_VENDOR_NV 0x03 I think this should be NVIDIA for consistency with other naming in the kernel, at least on Tegra. Otherwise: Reviewed-by: Thierry Reding <treding@xxxxxxxxxx>
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