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authorMauro Carvalho Chehab <mchehab@redhat.com>2008-11-19 06:17:44 -0300
committerMauro Carvalho Chehab <mchehab@redhat.com>2008-11-20 17:20:14 -0200
commitf2a2e4910502e866833732f31ee697d15b3e56fd (patch)
tree0679969d675d9e785c6c92a3625ce8df759e0cc3 /drivers/media/video
parentc4a98793a63c423c9e1af51822325969e23c16d4 (diff)
V4L/DVB (9647): em28xx: void having two concurrent control URB's
Now that we have a polling task for IR, there's a race condition, since IR can be polling while other operations are being doing. Also, we are now sharing the same urb_buf for both read and write control urb operations. So, we need a mutex. Thanks to Davin Heitmueller <devin.heitmueller@gmail.com> for warning me. Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video')
-rw-r--r--drivers/media/video/em28xx/em28xx-core.c12
-rw-r--r--drivers/media/video/em28xx/em28xx-video.c1
-rw-r--r--drivers/media/video/em28xx/em28xx.h1
3 files changed, 12 insertions, 2 deletions
diff --git a/drivers/media/video/em28xx/em28xx-core.c b/drivers/media/video/em28xx/em28xx-core.c
index 9551b8ab8c4..15e2b525310 100644
--- a/drivers/media/video/em28xx/em28xx-core.c
+++ b/drivers/media/video/em28xx/em28xx-core.c
@@ -76,18 +76,22 @@ int em28xx_read_reg_req_len(struct em28xx *dev, u8 req, u16 reg,
em28xx_regdbg("req=%02x, reg=%02x ", req, reg);
+ mutex_lock(&dev->ctrl_urb_lock);
ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), req,
USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
0x0000, reg, dev->urb_buf, len, HZ);
if (ret < 0) {
if (reg_debug)
printk(" failed!\n");
+ mutex_unlock(&dev->ctrl_urb_lock);
return ret;
}
if (len)
memcpy(buf, dev->urb_buf, len);
+ mutex_unlock(&dev->ctrl_urb_lock);
+
if (reg_debug) {
printk("%02x values: ", ret);
for (byte = 0; byte < len; byte++)
@@ -112,16 +116,18 @@ int em28xx_read_reg_req(struct em28xx *dev, u8 req, u16 reg)
em28xx_regdbg("req=%02x, reg=%02x:", req, reg);
+ mutex_lock(&dev->ctrl_urb_lock);
ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0), req,
USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
0x0000, reg, dev->urb_buf, 1, HZ);
+ val = dev->urb_buf[0];
+ mutex_unlock(&dev->ctrl_urb_lock);
+
if (ret < 0) {
printk(" failed!\n");
return ret;
}
- val = dev->urb_buf[0];
-
if (reg_debug)
printk("%02x\n", (unsigned char) val);
@@ -156,10 +162,12 @@ int em28xx_write_regs_req(struct em28xx *dev, u8 req, u16 reg, char *buf,
printk("\n");
}
+ mutex_lock(&dev->ctrl_urb_lock);
memcpy(dev->urb_buf, buf, len);
ret = usb_control_msg(dev->udev, usb_sndctrlpipe(dev->udev, 0), req,
USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
0x0000, reg, dev->urb_buf, len, HZ);
+ mutex_unlock(&dev->ctrl_urb_lock);
if (dev->wait_after_write)
msleep(dev->wait_after_write);
diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c
index bca5955339b..c32fc7d24a4 100644
--- a/drivers/media/video/em28xx/em28xx-video.c
+++ b/drivers/media/video/em28xx/em28xx-video.c
@@ -1936,6 +1936,7 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev,
dev->udev = udev;
mutex_init(&dev->lock);
+ mutex_init(&dev->ctrl_urb_lock);
spin_lock_init(&dev->slock);
init_waitqueue_head(&dev->open);
init_waitqueue_head(&dev->wait_frame);
diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h
index 1adf3d9d9bf..5956e9b3062 100644
--- a/drivers/media/video/em28xx/em28xx.h
+++ b/drivers/media/video/em28xx/em28xx.h
@@ -433,6 +433,7 @@ struct em28xx {
/* locks */
struct mutex lock;
+ struct mutex ctrl_urb_lock; /* protects urb_buf */
/* spinlock_t queue_lock; */
struct list_head inqueue, outqueue;
wait_queue_head_t open, wait_frame, wait_stream;