diff options
| author | Hans de Goede <hdegoede@redhat.com> | 2011-07-03 18:50:51 +0400 |
|---|---|---|
| committer | Mauro Carvalho Chehab <mchehab@redhat.com> | 2011-07-28 00:53:45 +0400 |
| commit | c11271349ad5d4647e69e511fc481b2dd390efc4 (patch) | |
| tree | bc9ecda60fb903856dae5e21271e449e203a14bc /drivers/media/video/pwc/pwc-v4l.c | |
| parent | 6c9cac89c009c049a9ad29cdf0f51892410fe751 (diff) | |
| download | linux-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/pwc-v4l.c')
| -rw-r--r-- | drivers/media/video/pwc/pwc-v4l.c | 36 |
1 files changed, 32 insertions, 4 deletions
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; } |