On 01/28/2015 05:37 PM, 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. 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]; ? Regards, Tvrtko _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/dri-devel
