Am 27.09.21 um 10:42 schrieb Pekka Paalanen:
On Fri, 3 Sep 2021 11:47:59 -0700
Rob Clark <robdclark@xxxxxxxxx> wrote:
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.
Signed-off-by: Rob Clark <robdclark@xxxxxxxxxxxx>
---
drivers/dma-buf/sync_file.c | 19 +++++++++++++++++++
include/uapi/linux/sync_file.h | 20 ++++++++++++++++++++
2 files changed, 39 insertions(+)
diff --git a/drivers/dma-buf/sync_file.c b/drivers/dma-buf/sync_file.c
index 394e6e1e9686..f295772d5169 100644
--- a/drivers/dma-buf/sync_file.c
+++ b/drivers/dma-buf/sync_file.c
@@ -459,6 +459,22 @@ 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)
{
@@ -471,6 +487,9 @@ 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..f67d4ffe7566 100644
--- a/include/uapi/linux/sync_file.h
+++ b/include/uapi/linux/sync_file.h
@@ -67,6 +67,18 @@ 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
Hi Rob,
I think you need to specify which clock this timestamp must be in.
Which epoch? Sounds a bit like CLOCK_REALTIME to me which would not
make sense.
Most likely CLOCK_MONOTONIC I think since that's what ktime is based on
as well IIRC.
My recollection might be wrong but I think Daniel documented somewhere
that an absolut 64bit nanosecond value should be used for timeouts in
IOCTLs which is sufficient for ~500 years uptime.
So the separation between seconds and nanoseconds might be redundant.
Regards,
Christian.
Also I cannot guess how a compositor should be using this, so
explaining the expected usage would be really good, with reasons for
why should userspace bother.
Thanks,
pq
+ */
+struct sync_set_deadline {
+ __s64 tv_sec;
+ __s32 tv_nsec;
+ __u32 pad;
+};
+
#define SYNC_IOC_MAGIC '>'
/**
@@ -95,4 +107,12 @@ 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 */
