Am 20.02.23 um 17:09 schrieb Rob Clark:
On Mon, Feb 20, 2023 at 12:27 AM Christian König
<christian.koenig@xxxxxxx> wrote:
Am 18.02.23 um 22:15 schrieb Rob Clark:
From: Rob Clark <robdclark@xxxxxxxxxxxx>
The initial purpose is for igt tests, but this would also be useful for
compositors that wait until close to vblank deadline to make decisions
about which frame to show.
The igt tests can be found at:
https://gitlab.freedesktop.org/robclark/igt-gpu-tools/-/commits/fence-deadline
v2: Clarify the timebase, add link to igt tests
Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
---
drivers/dma-buf/sync_file.c | 19 +++++++++++++++++++
include/uapi/linux/sync_file.h | 22 ++++++++++++++++++++++
2 files changed, 41 insertions(+)
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index af57799c86ce..fb6ca1032885 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -350,6 +350,22 @@ static long sync_file_ioctl_fence_info(struct sync_file *sync_file,
return ret;
}
+static int sync_file_ioctl_set_deadline(struct sync_file *sync_file,
+ unsigned long arg)
+{
+ struct sync_set_deadline ts;
+
+ if (copy_from_user(&ts, (void __user *)arg, sizeof(ts)))
+ return -EFAULT;
+
+ if (ts.pad)
+ return -EINVAL;
+
+ dma_fence_set_deadline(sync_file->fence, ktime_set(ts.tv_sec, ts.tv_nsec));
+
+ return 0;
+}
+
static long sync_file_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
@@ -362,6 +378,9 @@ static long sync_file_ioctl(struct file *file, unsigned int cmd,
case SYNC_IOC_FILE_INFO:
return sync_file_ioctl_fence_info(sync_file, arg);
+ case SYNC_IOC_SET_DEADLINE:
+ return sync_file_ioctl_set_deadline(sync_file, arg);
+
default:
return -ENOTTY;
}
diff --git a/include/uapi/linux/sync_file.h b/include/uapi/linux/sync_file.h
index ee2dcfb3d660..c8666580816f 100644
--- a/include/uapi/linux/sync_file.h
+++ b/include/uapi/linux/sync_file.h
@@ -67,6 +67,20 @@ struct sync_file_info {
__u64 sync_fence_info;
};
+/**
+ * struct sync_set_deadline - set a deadline on a fence
+ * @tv_sec: seconds elapsed since epoch
+ * @tv_nsec: nanoseconds elapsed since the time given by the tv_sec
+ * @pad: must be zero
+ *
+ * The timebase for the deadline is CLOCK_MONOTONIC (same as vblank)
+ */
+struct sync_set_deadline {
+ __s64 tv_sec;
+ __s32 tv_nsec;
+ __u32 pad;
IIRC struct timespec defined this as time_t/long (which is horrible for
an UAPI because of the sizeof(long) dependency), one possible
alternative is to use 64bit nanoseconds from CLOCK_MONOTONIC (which is
essentially ktime).
Not 100% sure if there is any preferences documented, but I think the
later might be better.
The original thought is that this maps directly to clock_gettime()
without extra conversion needed, and is similar to other pre-ktime_t
UAPI. But OTOH if userspace wants to add an offset, it is maybe
better to convert completely to ns in userspace and use a u64 (as that
is what ns_to_ktime() uses).. (and OFC whatever decision here also
applies to the syncobj wait ioctls)
I'm leaning towards u64 CLOCK_MONOTONIC ns if no one has a good
argument against that.
+1 for that.
Regards,
Christian.
BR,
-R
Either way the patch is Acked-by: Christian König
<christian.koenig@xxxxxxx> for this patch.
Regards,
Christian.
+};
+
#define SYNC_IOC_MAGIC '>'
/**
@@ -95,4 +109,12 @@ struct sync_file_info {
*/
#define SYNC_IOC_FILE_INFO _IOWR(SYNC_IOC_MAGIC, 4, struct sync_file_info)
+
+/**
+ * DOC: SYNC_IOC_SET_DEADLINE - set a deadline on a fence
+ *
+ * Allows userspace to set a deadline on a fence, see dma_fence_set_deadline()
+ */
+#define SYNC_IOC_SET_DEADLINE _IOW(SYNC_IOC_MAGIC, 5, struct sync_set_deadline)
+
#endif /* _UAPI_LINUX_SYNC_H */
