[PATCH v9 14/15] v4l: Add V4L2_CAP_FENCES to drivers

[Ezequiel Garcia <ezequiel@collabora.com>]

From: Gustavo Padovan <gustavo.padovan@collabora.com>

Drivers that use videobuf2 are capable of using fences and
should report that to userspace.

v9: Add in the core.

Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.com>
Signed-off-by: Ezequiel Garcia <ezequiel@collabora.com>
---
 drivers/media/v4l2-core/v4l2-ioctl.c | 8 ++++++++
 include/media/v4l2-fh.h              | 2 --
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/media/v4l2-core/v4l2-ioctl.c b/drivers/media/v4l2-core/v4l2-ioctl.c
index f75ad954a6f2..2ae527ef0bc7 100644
--- a/drivers/media/v4l2-core/v4l2-ioctl.c
+++ b/drivers/media/v4l2-core/v4l2-ioctl.c
@@ -1002,12 +1002,20 @@ static int v4l_querycap(const struct v4l2_ioctl_ops *ops,
 {
 	struct v4l2_capability *cap = (struct v4l2_capability *)arg;
 	struct video_device *vfd = video_devdata(file);
+	struct v4l2_fh *vfh =
+		test_bit(V4L2_FL_USES_V4L2_FH, &vfd->flags) ? fh : NULL;
 	int ret;
 
 	cap->version = LINUX_VERSION_CODE;
 	cap->device_caps = vfd->device_caps;
 	cap->capabilities = vfd->device_caps | V4L2_CAP_DEVICE_CAPS;
 
+	/* If it has a queue or a m2m context, then the
+	 * device supports fence synchronization.
+	 */
+	if (vfd->queue || (vfh && vfh->m2m_ctx))
+		cap->device_caps |= V4L2_CAP_FENCES;
+
 	ret = ops->vidioc_querycap(file, fh, cap);
 
 	cap->capabilities |= V4L2_CAP_EXT_PIX_FORMAT;
diff --git a/include/media/v4l2-fh.h b/include/media/v4l2-fh.h
index ea73fef8bdc0..e993ddc06991 100644
--- a/include/media/v4l2-fh.h
+++ b/include/media/v4l2-fh.h
@@ -57,9 +57,7 @@ struct v4l2_fh {
 	unsigned int		navailable;
 	u32			sequence;
 
-#if IS_ENABLED(CONFIG_V4L2_MEM2MEM_DEV)
 	struct v4l2_m2m_ctx	*m2m_ctx;
-#endif
 };
 
 /**
-- 
2.16.3