[media] au0828: fix race condition that causes xc5000 to not bind for digital

In some cases users would see the xc5000_attach() call failing for the
digital side of the tuner on initialization.  This is because of udev
running v4l-id while the digital side of the board is still coming up.

This is the exact same race condition which was present in em28xx (not
surprising since I copied all the locking logic from that driver when I
added analog support).  Reproduce Mauro's fix from the em28xx driver in
au0828.

Reported-by: Rick Harding <rharding@mitechie.com>
Signed-off-by: Devin Heitmueller <dheitmueller@kernellabs.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

diff --git a/drivers/media/video/au0828/au0828-core.c b/drivers/media/video/au0828/au0828-core.c
index 1e4ce5068ec2db52ca634f9a90e12ad66f755f6b..b2c4254e6ec3a519462e23e7565a036c49af23dd 100644 (file)
--- a/drivers/media/video/au0828/au0828-core.c
+++ b/drivers/media/video/au0828/au0828-core.c
@@ -205,6 +205,8 @@ static int au0828_usb_probe(struct usb_interface *interface,
                return -ENOMEM;
        }
 
+       mutex_init(&dev->lock);
+       mutex_lock(&dev->lock);
        mutex_init(&dev->mutex);
        mutex_init(&dev->dvb.lock);
        dev->usbdev = usbdev;
@@ -215,6 +217,7 @@ static int au0828_usb_probe(struct usb_interface *interface,
        if (retval) {
                printk(KERN_ERR "%s() v4l2_device_register failed\n",
                       __func__);
+               mutex_unlock(&dev->lock);
                kfree(dev);
                return -EIO;
        }
@@ -245,6 +248,8 @@ static int au0828_usb_probe(struct usb_interface *interface,
        printk(KERN_INFO "Registered device AU0828 [%s]\n",
                dev->board.name == NULL ? "Unset" : dev->board.name);
 
+       mutex_unlock(&dev->lock);
+
        return 0;
 }
 

diff --git a/drivers/media/video/au0828/au0828-video.c b/drivers/media/video/au0828/au0828-video.c
index 6e30c094c56f8bb9be742521ae1e64d624fed084..b1f8d1856eec1f5fd31f7e7eea7e71fa55875a0a 100644 (file)
--- a/drivers/media/video/au0828/au0828-video.c
+++ b/drivers/media/video/au0828/au0828-video.c
@@ -864,17 +864,15 @@ static int res_get(struct au0828_fh *fh, unsigned int bit)
                return 1;
 
        /* is it free? */
-       mutex_lock(&dev->lock);
        if (dev->resources & bit) {
                /* no, someone else uses it */
-               mutex_unlock(&dev->lock);
                return 0;
        }
        /* it's free, grab it */
        fh->resources  |= bit;
        dev->resources |= bit;
        dprintk(1, "res: get %d\n", bit);
-       mutex_unlock(&dev->lock);
+
        return 1;
 }
 
@@ -894,11 +892,9 @@ static void res_free(struct au0828_fh *fh, unsigned int bits)
 
        BUG_ON((fh->resources & bits) != bits);
 
-       mutex_lock(&dev->lock);
        fh->resources  &= ~bits;
        dev->resources &= ~bits;
        dprintk(1, "res: put %d\n", bits);
-       mutex_unlock(&dev->lock);
 }
 
 static int get_ressource(struct au0828_fh *fh)
@@ -1023,7 +1019,8 @@ static int au0828_v4l2_open(struct file *filp)
                                    NULL, &dev->slock,
                                    V4L2_BUF_TYPE_VIDEO_CAPTURE,
                                    V4L2_FIELD_INTERLACED,
-                                   sizeof(struct au0828_buffer), fh, NULL);
+                                   sizeof(struct au0828_buffer), fh,
+                                   &dev->lock);
 
        /* VBI Setup */
        dev->vbi_width = 720;
@@ -1032,8 +1029,8 @@ static int au0828_v4l2_open(struct file *filp)
                                    NULL, &dev->slock,
                                    V4L2_BUF_TYPE_VBI_CAPTURE,
                                    V4L2_FIELD_SEQ_TB,
-                                   sizeof(struct au0828_buffer), fh, NULL);
-
+                                   sizeof(struct au0828_buffer), fh,
+                                   &dev->lock);
        return ret;
 }
 
@@ -1312,8 +1309,6 @@ static int vidioc_s_fmt_vid_cap(struct file *file, void *priv,
        if (rc < 0)
                return rc;
 
-       mutex_lock(&dev->lock);
-
        if (videobuf_queue_is_busy(&fh->vb_vidq)) {
                printk(KERN_INFO "%s queue busy\n", __func__);
                rc = -EBUSY;
@@ -1322,7 +1317,6 @@ static int vidioc_s_fmt_vid_cap(struct file *file, void *priv,
 
        rc = au0828_set_format(dev, VIDIOC_S_FMT, f);
 out:
-       mutex_unlock(&dev->lock);
        return rc;
 }
 
@@ -1832,7 +1826,7 @@ static struct v4l2_file_operations au0828_v4l_fops = {
        .read       = au0828_v4l2_read,
        .poll       = au0828_v4l2_poll,
        .mmap       = au0828_v4l2_mmap,
-       .ioctl      = video_ioctl2,
+       .unlocked_ioctl = video_ioctl2,
 };
 
 static const struct v4l2_ioctl_ops video_ioctl_ops = {
@@ -1922,7 +1916,6 @@ int au0828_analog_register(struct au0828_dev *dev,
 
        init_waitqueue_head(&dev->open);
        spin_lock_init(&dev->slock);
-       mutex_init(&dev->lock);
 
        /* init video dma queues */
        INIT_LIST_HEAD(&dev->vidq.active);
@@ -1963,11 +1956,13 @@ int au0828_analog_register(struct au0828_dev *dev,
        /* Fill the video capture device struct */
        *dev->vdev = au0828_video_template;
        dev->vdev->parent = &dev->usbdev->dev;
+       dev->vdev->lock = &dev->lock;
        strcpy(dev->vdev->name, "au0828a video");
 
        /* Setup the VBI device */
        *dev->vbi_dev = au0828_video_template;
        dev->vbi_dev->parent = &dev->usbdev->dev;
+       dev->vbi_dev->lock = &dev->lock;
        strcpy(dev->vbi_dev->name, "au0828a vbi");
 
        /* Register the v4l2 device */