Hi Mauro,
Thanks for your feedback.
On Mon, Feb 1, 2016 at 7:33 AM, Mauro Carvalho Chehab
<mchehab@xxxxxxxxxxxxxxx> wrote:
Em Fri, 29 Jan 2016 11:05:04 -0800
Jean-Baptiste Theou <jtheou@xxxxxxxxxxxxxxxxxx> escreveu:
For tuners with no_alt_vanc=0, and VBI and analog video device
open.
There is two ways to close the devices:
*First way (start with user=2)
VBI first (user=1): URBs for the VBI are killed properly
with cx231xx_uninit_vbi_isoc
Analog second (user=0): URBs for the Analog are killed
properly with cx231xx_uninit_isoc
*Second way (start with user=2)
Analog first (user=1): URBs for the Analog are NOT killed
properly with cx231xx_uninit_isoc, because the exit path
is not called this time.
VBI first (user=0): URBs for the VBI are killed properly with
cx231xx_uninit_vbi_isoc, but we are exiting the function
without killing the URBs for the Analog
This situation lead to various kernel panics, since
the URBs are still processed, without the device been
open.
The patch fix the issue by calling the exit path no matter
what, when user=0, plus remove a duplicate trace.
Signed-off-by: Jean-Baptiste Theou <jtheou@xxxxxxxxxxxxxxxxxx>
---
- v2: Avoid duplicate code and ensure that the queue are freed
properly.
---
drivers/media/usb/cx231xx/cx231xx-video.c | 44
+++++++++----------------------
1 file changed, 12 insertions(+), 32 deletions(-)
diff --git a/drivers/media/usb/cx231xx/cx231xx-video.c
b/drivers/media/usb/cx231xx/cx231xx-video.c
index 9b88cd8..a832c83 100644
--- a/drivers/media/usb/cx231xx/cx231xx-video.c
+++ b/drivers/media/usb/cx231xx/cx231xx-video.c
@@ -1836,10 +1836,21 @@ static int cx231xx_close(struct file *filp)
cx231xx_videodbg("users=%d\n", dev->users);
- cx231xx_videodbg("users=%d\n", dev->users);
if (res_check(fh))
res_free(fh);
+ videobuf_stop(&fh->vb_vidq);
+ videobuf_mmap_free(&fh->vb_vidq);
+
+ /* the device is already disconnect,
+ * free the remaining resources
+ */
+ if (dev->state & DEV_DISCONNECTED) {
+ cx231xx_release_resources(dev);
+ fh->dev = NULL;
+ return 0;
+ }
+
/*
* To workaround error number=-71 on EP0 for VideoGrabber,
* need exclude following.
Hmm... The above doesn't sound right to stop the queue
unconditionally when
users != 0, as one could do weird things like:
start video
start vbi
stop vbi
start vbi
stop video
stop vbi
Those weird workflows happen when someone is using a TV application
like TVtime for capturing images, while using a different app, like
zvbi to get VBI data.
So, I guess that the above hunked should be removed...
@@ -1848,19 +1859,6 @@ static int cx231xx_close(struct file *filp)
*/
if (!dev->board.no_alt_vanc)
if (fh->type == V4L2_BUF_TYPE_VBI_CAPTURE) {
- videobuf_stop(&fh->vb_vidq);
- videobuf_mmap_free(&fh->vb_vidq);
-
- /* the device is already disconnect,
- free the remaining resources */
- if (dev->state & DEV_DISCONNECTED) {
- if (atomic_read(&dev->devlist_count) > 0) {
- cx231xx_release_resources(dev);
- fh->dev = NULL;
- return 0;
- }
- return 0;
- }
/* do this before setting alternate! */
cx231xx_uninit_vbi_isoc(dev);
@@ -1870,29 +1868,11 @@ static int cx231xx_close(struct file *filp)
cx231xx_set_alt_setting(dev, INDEX_VANC, 0);
else
cx231xx_set_alt_setting(dev, INDEX_HANC, 0);
-
- v4l2_fh_del(&fh->fh);
- v4l2_fh_exit(&fh->fh);
- kfree(fh);
- dev->users--;
- wake_up_interruptible(&dev->open);
- return 0;
}
The above changes are OK...
v4l2_fh_del(&fh->fh);
dev->users--;
if (!dev->users) {
- videobuf_stop(&fh->vb_vidq);
- videobuf_mmap_free(&fh->vb_vidq);
-
- /* the device is already disconnect,
- free the remaining resources */
- if (dev->state & DEV_DISCONNECTED) {
- cx231xx_release_resources(dev);
- fh->dev = NULL;
- return 0;
- }
-
But the above code should be kept, as we should only stop/free
resources when neither VBI or Video is running. Other drivers do
similar things and work properly. See em28xx for example (I'm sure
em28xx video/vbi is working as expected, as I did such tests last
week).
My understanding of this code is that the VBI and the VIDEO device have
they own vb_vidq,
so if videobuf_stop and video_mmap_free are called only when user=0,
one device
(the first one to be close) will not be freed properly.
This is why I am stopping the use of the buffers and release the memory
first for every call
of close().
Am I missing the way this code works?
/* Save some power by putting tuner to sleep */
call_all(dev, core, s_power, 0);
Regards,
Mauro
Best regards,
Jean-Baptiste
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