The pwc driver used to:
1. kmalloc a buffer
2. memcpy data to send over usb there
3. do the usb_control_msg call (which does not work with data on the stack)
4. free the buffer
For every usb command send. This patch changes the code to instead malloc
a buffer for this purpose once and use it everywhere.
[mchehab@redhat.com: Fix a compilation breakage with allyesconfig:
drivers/media/video/pwc/pwc-ctrl.c: In function ‘pwc_get_cmos_sensor’:
drivers/media/video/pwc/pwc-ctrl.c:546:3: warning: passing argument 4 of ‘recv_control_msg’ makes integer from pointer without a cast [en$
drivers/media/video/pwc/pwc-ctrl.c:107:12: note: expected ‘int’ but argument is of type ‘unsigned char *’
drivers/media/video/pwc/pwc-ctrl.c:546:3: error: too many arguments to function ‘recv_control_msg’
drivers/media/video/pwc/pwc-ctrl.c:107:12: note: declared here]
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
The in kernel version of the pwc driver has never supported snapshot
mode, and now that we no longer support the pixfmt.priv abuse there also
no longer is a way for userspace to request it, rendering all the code in
question dead (never called), so remove it.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
While testing gtk-v4l's new ctrl event code, I hit the following deadlock
in the pwc driver:
Thread 1:
-Does a VIDIOC_G_CTRL
-video2_ioctl takes the modlock
-video2_ioctl calls v4l2_g_ctrl
-v4l2_g_ctrl takes the ctrl_handler lock
-v4l2_g_ctrl calls pwc_g_volatile_ctrl
-pwc_g_volatile_ctrl releases the modlock as the usb transfer can take a
significant amount of time and we don't want to block DQBUF / QBUF too long
Thread 2:
-Does a VIDIOC_FOO_CTRL
-video2_ioctl takes the modlock
-video2_ioctl calls v4l2_foo_ctrl
-v4l2_foo_ctrl blocks while trying to take the ctrl_handler lock
Thread 1:
-Blocks while trying to re-take the modlock, as its caller will eventually
unlock that
Now we have thread 1 waiting for the modlock while holding the ctrl_handler
lock and thread 2 waiting for the ctrl_handler lock while holding the
modlock -> deadlock.
Conclusion:
1) We cannot unlock modlock from pwc_s_ctrl / pwc_g_volatile_ctrl,
but this can cause QBUF / DQBUF to block for up to a full second
2) After evaluating various option I came to the conclusion that pwc should
stop using the v4l2 core locking, and instead do its own locking
Thus this patch stops pwc using the v4l2 core locking, and replaces that with
it doing its own locking where necessary.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Doing a bunch of initialization every time /dev/video is opened, and thus
for example when the udev rules probe for capabilities makes no sense,
do it at driver load, resp. stream start instead.
This is a preparation patch for allowing multiple opens of the /dev/video
node.
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Add v4l2 compatibility
Include the decompressor (legal problem has been resolv by Alan Cox)
Faster decoder and easier to maintain, optimize, ...
Can export to userland compressed stream
Support more cameras, lot of bugs are fixed.
Signed-off-by: Luc Saillard <luc@saillard.org>
Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
Hans de Goede