Hi Hans,
Am 18.09.2014 um 21:13 schrieb Hans Verkuil:
> 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.
You are 100% right, v4l2_fh_is_singular() is a per device _node_ check.
How could I miss that ? :/
> 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.
Indeed. I will send a revert patch.
Thanks for the hint !
Regards,
Frank
>
> 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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