Hi Frank,
On 07/25/2014 07:48 PM, Frank Schäfer wrote:
> Instead of counting the number of opened file handles, use function
> v4l2_fh_is_singular_file() in em28xx_v4l2_open() and em28xx_v4l2_close() to
> determine if the file handle is the first/last opened one.
This won't work: if you capture from both /dev/video and /dev/vbi and close
one, then it stops all streaming.
I would just revert this patch completely.
There is currently no core support for detecting when all users of all devices
registered by a driver have left, so you don't have really have an alternative
but to use your old code.
Regards,
Hans
>
> Signed-off-by: Frank Schäfer <fschaefer.oss@xxxxxxxxxxxxxx>
> ---
> drivers/media/usb/em28xx/em28xx-video.c | 23 +++++++++++++----------
> drivers/media/usb/em28xx/em28xx.h | 1 -
> 2 files changed, 13 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/media/usb/em28xx/em28xx-video.c b/drivers/media/usb/em28xx/em28xx-video.c
> index 3a7ec3b..087ccf9 100644
> --- a/drivers/media/usb/em28xx/em28xx-video.c
> +++ b/drivers/media/usb/em28xx/em28xx-video.c
> @@ -1883,9 +1883,8 @@ static int em28xx_v4l2_open(struct file *filp)
> return -EINVAL;
> }
>
> - em28xx_videodbg("open dev=%s type=%s users=%d\n",
> - video_device_node_name(vdev), v4l2_type_names[fh_type],
> - v4l2->users);
> + em28xx_videodbg("open dev=%s type=%s\n",
> + video_device_node_name(vdev), v4l2_type_names[fh_type]);
>
> if (mutex_lock_interruptible(&dev->lock))
> return -ERESTARTSYS;
> @@ -1898,7 +1897,9 @@ static int em28xx_v4l2_open(struct file *filp)
> return ret;
> }
>
> - if (v4l2->users == 0) {
> + if (v4l2_fh_is_singular_file(filp)) {
> + em28xx_videodbg("first opened filehandle, initializing device\n");
> +
> em28xx_set_mode(dev, EM28XX_ANALOG_MODE);
>
> if (vdev->vfl_type != VFL_TYPE_RADIO)
> @@ -1909,6 +1910,8 @@ static int em28xx_v4l2_open(struct file *filp)
> * of some i2c devices
> */
> em28xx_wake_i2c(dev);
> + } else {
> + em28xx_videodbg("further filehandles are already opened\n");
> }
>
> if (vdev->vfl_type == VFL_TYPE_RADIO) {
> @@ -1918,7 +1921,6 @@ static int em28xx_v4l2_open(struct file *filp)
>
> kref_get(&dev->ref);
> kref_get(&v4l2->ref);
> - v4l2->users++;
>
> mutex_unlock(&dev->lock);
>
> @@ -2025,12 +2027,11 @@ static int em28xx_v4l2_close(struct file *filp)
> struct em28xx_v4l2 *v4l2 = dev->v4l2;
> int errCode;
>
> - em28xx_videodbg("users=%d\n", v4l2->users);
> -
> - vb2_fop_release(filp);
> mutex_lock(&dev->lock);
>
> - if (v4l2->users == 1) {
> + if (v4l2_fh_is_singular_file(filp)) {
> + em28xx_videodbg("last opened filehandle, shutting down device\n");
> +
> /* No sense to try to write to the device */
> if (dev->disconnected)
> goto exit;
> @@ -2049,10 +2050,12 @@ static int em28xx_v4l2_close(struct file *filp)
> em28xx_errdev("cannot change alternate number to "
> "0 (error=%i)\n", errCode);
> }
> + } else {
> + em28xx_videodbg("further opened filehandles left\n");
> }
>
> exit:
> - v4l2->users--;
> + vb2_fop_release(filp);
> kref_put(&v4l2->ref, em28xx_free_v4l2);
> mutex_unlock(&dev->lock);
> kref_put(&dev->ref, em28xx_free_device);
> diff --git a/drivers/media/usb/em28xx/em28xx.h b/drivers/media/usb/em28xx/em28xx.h
> index 4360338..84ef8ef 100644
> --- a/drivers/media/usb/em28xx/em28xx.h
> +++ b/drivers/media/usb/em28xx/em28xx.h
> @@ -524,7 +524,6 @@ struct em28xx_v4l2 {
> int sensor_yres;
> int sensor_xtal;
>
> - int users; /* user count for exclusive use */
> int streaming_users; /* number of actively streaming users */
>
> u32 frequency; /* selected tuner frequency */
>
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