[media] gspca: Use req_events in poll

So that we don't start a read stream when an app is only polling for control
events.

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/video/gspca/gspca.c b/drivers/media/video/gspca/gspca.c
index d9df309..8b97f77 100644 (file)
--- a/drivers/media/video/gspca/gspca.c
+++ b/drivers/media/video/gspca/gspca.c
@@ -2030,31 +2030,39 @@ out:
 static unsigned int dev_poll(struct file *file, poll_table *wait)
 {
        struct gspca_dev *gspca_dev = video_drvdata(file);
-       int ret;
+       unsigned long req_events = poll_requested_events(wait);
+       int ret = 0;
 
        PDEBUG(D_FRAM, "poll");
 
-       poll_wait(file, &gspca_dev->wq, wait);
+       if (req_events & POLLPRI)
+               ret |= v4l2_ctrl_poll(file, wait);
 
-       /* if reqbufs is not done, the user would use read() */
-       if (gspca_dev->memory == GSPCA_MEMORY_NO) {
-               ret = read_alloc(gspca_dev, file);
-               if (ret != 0)
-                       return POLLERR;
-       }
+       if (req_events & (POLLIN | POLLRDNORM)) {
+               /* if reqbufs is not done, the user would use read() */
+               if (gspca_dev->memory == GSPCA_MEMORY_NO) {
+                       if (read_alloc(gspca_dev, file) != 0) {
+                               ret |= POLLERR;
+                               goto out;
+                       }
+               }
 
-       if (mutex_lock_interruptible(&gspca_dev->queue_lock) != 0)
-               return POLLERR;
+               poll_wait(file, &gspca_dev->wq, wait);
 
-       /* check if an image has been received */
-       if (gspca_dev->fr_o != atomic_read(&gspca_dev->fr_i))
-               ret = POLLIN | POLLRDNORM;      /* yes */
-       else
-               ret = 0;
-       ret |= v4l2_ctrl_poll(file, wait);
-       mutex_unlock(&gspca_dev->queue_lock);
+               /* check if an image has been received */
+               if (mutex_lock_interruptible(&gspca_dev->queue_lock) != 0) {
+                       ret |= POLLERR;
+                       goto out;
+               }
+               if (gspca_dev->fr_o != atomic_read(&gspca_dev->fr_i))
+                       ret |= POLLIN | POLLRDNORM;
+               mutex_unlock(&gspca_dev->queue_lock);
+       }
+
+out:
        if (!gspca_dev->present)
-               return POLLHUP;
+               ret |= POLLHUP;
+
        return ret;
 }