Re: [PATCH] RFC: drm: add support for tiled/compressed/etc modifier in addfb2 (v1.5)

Daniel Vetter
2015-01-29T11:30:29Z

On Wed, Jan 28, 2015 at 05:57:56PM +0000, Tvrtko Ursulin wrote:
>
> On 01/28/2015 05:37 PM, Daniel Vetter wrote:
> >From: Rob Clark <robdclark@gmail.com>
> >
> >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.
> >The format modifiers are added at the end of the ioctl struct, so for
> >legacy userspace it will be zero padded.
> >
> >TODO how best to deal with assignment of modifier token values? The
> >rough idea was to namespace things with an 8bit vendor-id, and then
> >beyond that it is treated as an opaque value. But that was a relatively
> >arbitrary choice. There are cases where same tiling pattern and/or
> >compression is supported by various different vendors. So we should
> >standardize to use the vendor-id and value of the first one who
> >documents the format?
>
> Maybe:
> __u64 modifier[4];
> __u64 vendor_modifier[4];

Seems rendundant since the modifier added in this patch is already vendor
specific. Or what exactly are you trying to accomplish here?
-Daniel

>
> ?
>
> Regards,
>
> Tvrtko

--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
dri-devel@lists.freedesktop.org