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authorHans de Goede <hdegoede@redhat.com>2011-07-03 18:50:51 +0400
committerMauro Carvalho Chehab <mchehab@redhat.com>2011-07-28 00:53:45 +0400
commitc11271349ad5d4647e69e511fc481b2dd390efc4 (patch)
treebc9ecda60fb903856dae5e21271e449e203a14bc /drivers/media/video/pwc
parent6c9cac89c009c049a9ad29cdf0f51892410fe751 (diff)
downloadlinux-c11271349ad5d4647e69e511fc481b2dd390efc4.tar.xz
[media] pwc: Allow dqbuf / read to complete while waiting for controls
Signed-off-by: Hans de Goede <hdegoede@redhat.com> Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Diffstat (limited to 'drivers/media/video/pwc')
-rw-r--r--drivers/media/video/pwc/pwc-if.c3
-rw-r--r--drivers/media/video/pwc/pwc-v4l.c36
-rw-r--r--drivers/media/video/pwc/pwc.h3
3 files changed, 38 insertions, 4 deletions
diff --git a/drivers/media/video/pwc/pwc-if.c b/drivers/media/video/pwc/pwc-if.c
index 1d5a6db915fa..fdf113fe51c3 100644
--- a/drivers/media/video/pwc/pwc-if.c
+++ b/drivers/media/video/pwc/pwc-if.c
@@ -1160,6 +1160,7 @@ static int usb_pwc_probe(struct usb_interface *intf, const struct usb_device_id
pwc_construct(pdev); /* set min/max sizes correct */
mutex_init(&pdev->modlock);
+ mutex_init(&pdev->udevlock);
spin_lock_init(&pdev->queued_bufs_lock);
INIT_LIST_HEAD(&pdev->queued_bufs);
@@ -1297,6 +1298,7 @@ static void usb_pwc_disconnect(struct usb_interface *intf)
{
struct pwc_device *pdev = usb_get_intfdata(intf);
+ mutex_lock(&pdev->udevlock);
mutex_lock(&pdev->modlock);
usb_set_intfdata(intf, NULL);
@@ -1306,6 +1308,7 @@ static void usb_pwc_disconnect(struct usb_interface *intf)
pdev->udev = NULL;
mutex_unlock(&pdev->modlock);
+ mutex_unlock(&pdev->udevlock);
pwc_remove_sysfs_files(pdev);
video_unregister_device(&pdev->vdev);
diff --git a/drivers/media/video/pwc/pwc-v4l.c b/drivers/media/video/pwc/pwc-v4l.c
index 986dd5d6187a..537657283e79 100644
--- a/drivers/media/video/pwc/pwc-v4l.c
+++ b/drivers/media/video/pwc/pwc-v4l.c
@@ -526,8 +526,24 @@ static int pwc_g_volatile_ctrl(struct v4l2_ctrl *ctrl)
container_of(ctrl->handler, struct pwc_device, ctrl_handler);
int ret = 0;
- if (!pdev->udev)
- return -ENODEV;
+ /*
+ * Sometimes it can take quite long for the pwc to complete usb control
+ * transfers, so release the modlock to give streaming by another
+ * process / thread the chance to continue with a dqbuf.
+ */
+ mutex_unlock(&pdev->modlock);
+
+ /*
+ * Take the udev-lock to protect against the disconnect handler
+ * completing and setting dev->udev to NULL underneath us. Other code
+ * does not need to do this since it is protected by the modlock.
+ */
+ mutex_lock(&pdev->udevlock);
+
+ if (!pdev->udev) {
+ ret = -ENODEV;
+ goto leave;
+ }
switch (ctrl->id) {
case V4L2_CID_AUTO_WHITE_BALANCE:
@@ -590,6 +606,9 @@ static int pwc_g_volatile_ctrl(struct v4l2_ctrl *ctrl)
if (ret)
PWC_ERROR("g_ctrl %s error %d\n", ctrl->name, ret);
+leave:
+ mutex_unlock(&pdev->udevlock);
+ mutex_lock(&pdev->modlock);
return ret;
}
@@ -751,8 +770,14 @@ static int pwc_s_ctrl(struct v4l2_ctrl *ctrl)
container_of(ctrl->handler, struct pwc_device, ctrl_handler);
int ret = 0;
- if (!pdev->udev)
- return -ENODEV;
+ /* See the comments on locking in pwc_g_volatile_ctrl */
+ mutex_unlock(&pdev->modlock);
+ mutex_lock(&pdev->udevlock);
+
+ if (!pdev->udev) {
+ ret = -ENODEV;
+ goto leave;
+ }
switch (ctrl->id) {
case V4L2_CID_BRIGHTNESS:
@@ -841,6 +866,9 @@ static int pwc_s_ctrl(struct v4l2_ctrl *ctrl)
if (ret)
PWC_ERROR("s_ctrl %s error %d\n", ctrl->name, ret);
+leave:
+ mutex_unlock(&pdev->udevlock);
+ mutex_lock(&pdev->modlock);
return ret;
}
diff --git a/drivers/media/video/pwc/pwc.h b/drivers/media/video/pwc/pwc.h
index 601a549988b5..e02dbf745155 100644
--- a/drivers/media/video/pwc/pwc.h
+++ b/drivers/media/video/pwc/pwc.h
@@ -200,6 +200,9 @@ struct pwc_device
/* Pointer to our usb_device, may be NULL after unplug */
struct usb_device *udev;
+ /* Protects the setting of udev to NULL by our disconnect handler */
+ struct mutex udevlock;
+
/* type of cam (645, 646, 675, 680, 690, 720, 730, 740, 750) */
int type;
int release; /* release number */