On Wed, Oct 09, 2013 at 02:54:09PM +0300, Arto Merilainen wrote:
> This patch makes the necessary additions to deliver syncpoint base
> to the user space.
>
> This patch splits the index field in the drm_tegra_get_syncpt structure
> into three separate fields (index, support_base, base_id). This allows
> to keep compatibility over kernel versions:
> - The placing of index field stays constant and therefore the interface
> should stay compatible with earlier userspace versions.
> - The old index field was input-only and it was not supposed to be read
> afterwards. Delivering data back in the same field should not introduce
> regressions to any old user space applications.
> - Old kernels left support_base and base_id fields intact (zero) and
> hence the new user space applications get the correct response from
> the kernel (=syncpoint does not have a base).
>
> Signed-off-by: Arto Merilainen <amerilainen@xxxxxxxxxx>
> ---
> drivers/gpu/host1x/drm/drm.c | 2 ++
> include/uapi/drm/tegra_drm.h | 4 +++-
> 2 files changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/host1x/drm/drm.c b/drivers/gpu/host1x/drm/drm.c
> index 8c61cee..4251563 100644
> --- a/drivers/gpu/host1x/drm/drm.c
> +++ b/drivers/gpu/host1x/drm/drm.c
> @@ -468,6 +468,8 @@ static int tegra_get_syncpt(struct drm_device *drm, void *data,
>
> syncpt = context->client->syncpts[args->index];
> args->id = host1x_syncpt_id(syncpt);
> + args->support_base = syncpt->base ? 1 : 0;
> + args->base_id = syncpt->base ? syncpt->base->id : 0;
>
> return 0;
> }
> diff --git a/include/uapi/drm/tegra_drm.h b/include/uapi/drm/tegra_drm.h
> index 73bde4e..7a79ca5 100644
> --- a/include/uapi/drm/tegra_drm.h
> +++ b/include/uapi/drm/tegra_drm.h
> @@ -61,7 +61,9 @@ struct drm_tegra_close_channel {
>
> struct drm_tegra_get_syncpt {
> __u64 context;
> - __u32 index;
> + __u16 index;
> + __u8 support_base;
> + __u8 base_id;
> __u32 id;
I don't like this. Can't we just add a separate IOCTL? Something like:
struct drm_tegra_get_syncpt_base {
__u64 context;
__u32 syncpt;
__u32 base;
};
Which could be used somewhat like this:
struct drm_tegra_get_syncpt_base args;
memset(&args, 0, sizeof(args));
args.context = context;
args.syncpt = syncpt;
err = ioctl(fd, DRM_IOCTL_TEGRA_GET_SYNCPT_BASE, &args);
if (err < 0) {
/*
* perhaps errno == ENOTSUP if the syncpoint has no
* associated base?
*/
}
base = args.base;
Thierry
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