[PATCH] linux-dmabuf: clarify DRM_FORMAT_MOD_INVALID
olvaffe at gmail.com
Tue Apr 9 22:23:11 UTC 2019
Talked with Daniel offline. I sent a different version to revive the
On Mon, Apr 1, 2019 at 10:41 AM Chia-I Wu <olvaffe at gmail.com> wrote:
> DRM_FORMAT_MOD_INVALID means to derive the modifier from the dmabuf.
> Signed-off-by: Chia-I Wu <olvaffe at gmail.com>
> .../linux-dmabuf/linux-dmabuf-unstable-v1.xml | 15 ++++++++++++++-
> 1 file changed, 14 insertions(+), 1 deletion(-)
> diff --git a/unstable/linux-dmabuf/linux-dmabuf-unstable-v1.xml
> index 154afe2..7c76441 100644
> --- a/unstable/linux-dmabuf/linux-dmabuf-unstable-v1.xml
> +++ b/unstable/linux-dmabuf/linux-dmabuf-unstable-v1.xml
> @@ -28,6 +28,7 @@
> <description summary="factory for creating dmabuf-based wl_buffers">
> Following the interfaces from:
> and the Linux DRM sub-system's AddFb2 ioctl.
> This interface offers ways to create generic dmabuf-based
> @@ -129,8 +130,13 @@
> binds to this interface. A roundtrip after binding guarantees that
> the client has received all supported format-modifier pairs.
> + For each supported format, DRM_FORMAT_MOD_INVALID (that is,
> + modifier_hi == 0x00ffffff and modifier_lo == 0xffffffff) is
> + and may not be sent.
> For the definition of the format and modifier codes, see the
> - zwp_linux_buffer_params_v1::create request.
> + zwp_linux_buffer_params_v1::create and
> + requests.
> <arg name="format" type="uint" summary="DRM_FORMAT code"/>
> <arg name="modifier_hi" type="uint"
> @@ -200,6 +206,13 @@
> This request raises the PLANE_IDX error if plane_idx is too large.
> The error PLANE_SET is raised if attempting to set a plane that
> was already set.
> + Note that DRM_FORMAT_MOD_INVALID (that is, modifier_hi ==
> + and modifier_lo == 0xffffffff) is always allowed and has a special
> + meaning. It indicates that the modifier is derived from the
> dmabuf fd
> + rather than explicitly specified. This use is discouraged and may
> + work if the dmabuf is imported to a different device than the
> + that allocated it.
> <arg name="fd" type="fd" summary="dmabuf fd"/>
> <arg name="plane_idx" type="uint" summary="plane index"/>
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