[media] gspca_main: Allow switching from read to mmap / userptr mode

Some applications (xawtv, qv4l2) mix read and mmap calls. Allow switching
from read mode back to mmap mode (by doing a reqbufs).

Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Acked-by: Jean-Francois Moine <moinejf@free.fr>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/media/video/gspca/gspca.c b/drivers/media/video/gspca/gspca.c
index 244fb76eaead..4ab906be8962 100644
--- a/drivers/media/video/gspca/gspca.c
+++ b/drivers/media/video/gspca/gspca.c
@@ -1497,6 +1497,7 @@ static int vidioc_reqbufs(struct file *file, void *priv,
                 return -ERESTARTSYS;
 
         if (gspca_dev->memory != GSPCA_MEMORY_NO
+            && gspca_dev->memory != GSPCA_MEMORY_READ
             && gspca_dev->memory != rb->memory) {
                 ret = -EBUSY;
                 goto out;
@@ -1525,6 +1526,9 @@ static int vidioc_reqbufs(struct file *file, void *priv,
                 gspca_stream_off(gspca_dev);
                 mutex_unlock(&gspca_dev->usb_lock);
         }
+        /* Don't restart the stream when switching from read to mmap mode */
+        if (gspca_dev->memory == GSPCA_MEMORY_READ)
+                streaming = 0;
 
         /* free the previous allocated buffers, if any */
         if (gspca_dev->nframes != 0)