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V4L/DVB (6582): Fix em28xx to allow multiple open
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Allows shared access support for em28xx. Just one userspace application is
allowed to get stream. The other(s) application(s) can change V4L2 controls,
set video standards, etc.

This patch were splited from Markus Rechberger's tree and backported to 2.6.17
by Pádraig Brady.

The original patch were ported to the latest em28xx version and had CodingStyle
corrected to solve the issues pointed by scripts/checkpatch.pl.

Thanks to Pádraig Brady <P@draigBrady.com> for pointing this.

Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
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Mauro Carvalho Chehab committed Jan 25, 2008
1 parent 2c94a67 commit a3a048c
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Showing 2 changed files with 79 additions and 51 deletions.
124 changes: 73 additions & 51 deletions drivers/media/video/em28xx/em28xx-video.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -234,6 +234,7 @@ static int em28xx_v4l2_open(struct inode *inode, struct file *filp)
int minor = iminor(inode);
int errCode = 0;
struct em28xx *h,*dev = NULL;
struct em28xx_fh *fh;

list_for_each_entry(h, &em28xx_devlist, devlist) {
if (h->vdev->minor == minor) {
Expand All @@ -251,19 +252,17 @@ static int em28xx_v4l2_open(struct inode *inode, struct file *filp)
em28xx_videodbg("open minor=%d type=%s users=%d\n",
minor,v4l2_type_names[dev->type],dev->users);

mutex_lock(&dev->lock);
fh = kzalloc(sizeof(struct em28xx_fh), GFP_KERNEL);

if (dev->users) {
em28xx_warn("this driver can be opened only once\n");
mutex_unlock(&dev->lock);
return -EBUSY;
if (!fh) {
em28xx_errdev("em28xx-video.c: Out of memory?!\n");
return -ENOMEM;
}
mutex_lock(&dev->lock);
fh->dev = dev;
filp->private_data = fh;

spin_lock_init(&dev->queue_lock);
init_waitqueue_head(&dev->wait_frame);
init_waitqueue_head(&dev->wait_stream);

if (dev->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
if (dev->type == V4L2_BUF_TYPE_VIDEO_CAPTURE && dev->users == 0) {
em28xx_set_alternate(dev);

dev->width = norm_maxw(dev);
Expand All @@ -277,26 +276,16 @@ static int em28xx_v4l2_open(struct inode *inode, struct file *filp)
em28xx_capture_start(dev, 1);
em28xx_resolution_set(dev);

/* device needs to be initialized before isoc transfer */
video_mux(dev, 0);

/* start the transfer */
errCode = em28xx_init_isoc(dev);
if (errCode)
goto err;

em28xx_empty_framequeues(dev);
}

dev->users++;
filp->private_data = dev;
dev->io = IO_NONE;
dev->stream = STREAM_OFF;
dev->num_frames = 0;

/* prepare queues */
em28xx_empty_framequeues(dev);

dev->state |= DEV_INITIALIZED;

err:
mutex_unlock(&dev->lock);
Expand Down Expand Up @@ -333,34 +322,41 @@ static void em28xx_release_resources(struct em28xx *dev)
*/
static int em28xx_v4l2_close(struct inode *inode, struct file *filp)
{
int errCode;
struct em28xx *dev=filp->private_data;
struct em28xx_fh *fh = filp->private_data;
struct em28xx *dev = fh->dev;
int errCode;

em28xx_videodbg("users=%d\n", dev->users);

mutex_lock(&dev->lock);
if (fh->reader == 1)
fh->reader = 0;

em28xx_uninit_isoc(dev);
if (dev->users == 1) {
dev->reader = 0;

em28xx_release_buffers(dev);
em28xx_uninit_isoc(dev);
em28xx_release_buffers(dev);

/* the device is already disconnect, free the remaining resources */
if (dev->state & DEV_DISCONNECTED) {
em28xx_release_resources(dev);
mutex_unlock(&dev->lock);
kfree(dev);
return 0;
}
/* the device is already disconnect,
free the remaining resources */
if (dev->state & DEV_DISCONNECTED) {
em28xx_release_resources(dev);
mutex_unlock(&dev->lock);
kfree(dev);
return 0;
}

/* set alternate 0 */
dev->alt = 0;
em28xx_videodbg("setting alternate 0\n");
errCode = usb_set_interface(dev->udev, 0, 0);
if (errCode < 0) {
em28xx_errdev ("cannot change alternate number to 0 (error=%i)\n",
errCode);
/* set alternate 0 */
dev->alt = 0;
em28xx_videodbg("setting alternate 0\n");
errCode = usb_set_interface(dev->udev, 0, 0);
if (errCode < 0) {
em28xx_errdev("cannot change alternate number to "
"0 (error=%i)\n", errCode);
}
}

kfree(fh);
dev->users--;
wake_up_interruptible_nr(&dev->open, 1);
mutex_unlock(&dev->lock);
Expand All @@ -378,13 +374,19 @@ em28xx_v4l2_read(struct file *filp, char __user * buf, size_t count,
struct em28xx_frame_t *f, *i;
unsigned long lock_flags;
int ret = 0;
struct em28xx *dev = filp->private_data;
struct em28xx_fh *fh = filp->private_data;
struct em28xx *dev = fh->dev;

mutex_lock(&dev->lock);

if (dev->type == V4L2_BUF_TYPE_VIDEO_CAPTURE) {
if (dev->type == V4L2_BUF_TYPE_VIDEO_CAPTURE)
em28xx_videodbg("V4l2_Buf_type_videocapture is set\n");

if (dev->reader > 0 && fh->reader == 0) {
mutex_unlock(&dev->lock);
return -EBUSY;
}

if (dev->type == V4L2_BUF_TYPE_VBI_CAPTURE) {
em28xx_videodbg("V4L2_BUF_TYPE_VBI_CAPTURE is set\n");
em28xx_videodbg("not supported yet! ...\n");
Expand Down Expand Up @@ -423,6 +425,9 @@ em28xx_v4l2_read(struct file *filp, char __user * buf, size_t count,
" the device again to choose the read method\n");
mutex_unlock(&dev->lock);
return -EINVAL;
} else {
dev->reader = 1;
fh->reader = 1;
}

if (dev->io == IO_NONE) {
Expand Down Expand Up @@ -491,7 +496,8 @@ em28xx_v4l2_read(struct file *filp, char __user * buf, size_t count,
static unsigned int em28xx_v4l2_poll(struct file *filp, poll_table * wait)
{
unsigned int mask = 0;
struct em28xx *dev = filp->private_data;
struct em28xx_fh *fh = filp->private_data;
struct em28xx *dev = fh->dev;

mutex_lock(&dev->lock);

Expand Down Expand Up @@ -559,15 +565,23 @@ static struct vm_operations_struct em28xx_vm_ops = {
*/
static int em28xx_v4l2_mmap(struct file *filp, struct vm_area_struct *vma)
{
unsigned long size = vma->vm_end - vma->vm_start,
start = vma->vm_start;
void *pos;
u32 i;

struct em28xx *dev = filp->private_data;
struct em28xx_fh *fh = filp->private_data;
struct em28xx *dev = fh->dev;
unsigned long size = vma->vm_end - vma->vm_start;
unsigned long start = vma->vm_start;
void *pos;
u32 i;

mutex_lock(&dev->lock);

if (dev->reader > 0 && fh->reader == 0) {
mutex_unlock(&dev->lock);
return -EBUSY;
} else {
dev->reader = 1;
fh->reader = 1;
}

if (dev->state & DEV_DISCONNECTED) {
em28xx_videodbg("mmap: device not present\n");
mutex_unlock(&dev->lock);
Expand Down Expand Up @@ -918,6 +932,7 @@ static int em28xx_do_ioctl(struct inode *inode, struct file *filp,
struct em28xx *dev, unsigned int cmd, void *arg,
v4l2_kioctl driver_ioctl)
{
struct em28xx_fh *fh = filp->private_data;
int ret;

switch (cmd) {
Expand Down Expand Up @@ -1227,6 +1242,8 @@ static int em28xx_do_ioctl(struct inode *inode, struct file *filp,
return ret;
}
}

fh->reader = 0;
em28xx_empty_framequeues(dev);
mutex_unlock(&dev->lock);

Expand All @@ -1248,7 +1265,8 @@ static int em28xx_do_ioctl(struct inode *inode, struct file *filp,
static int em28xx_video_do_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, void *arg)
{
struct em28xx *dev = filp->private_data;
struct em28xx_fh *fh = filp->private_data;
struct em28xx *dev = fh->dev;

if (!dev)
return -ENODEV;
Expand Down Expand Up @@ -1456,7 +1474,8 @@ static int em28xx_v4l2_ioctl(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg)
{
int ret = 0;
struct em28xx *dev = filp->private_data;
struct em28xx_fh *fh = filp->private_data;
struct em28xx *dev = fh->dev;

if (dev->state & DEV_DISCONNECTED) {
em28xx_errdev("v4l2 ioctl: device not present\n");
Expand Down Expand Up @@ -1503,7 +1522,10 @@ static int em28xx_init_dev(struct em28xx **devhandle, struct usb_device *udev,

dev->udev = udev;
mutex_init(&dev->lock);
spin_lock_init(&dev->queue_lock);
init_waitqueue_head(&dev->open);
init_waitqueue_head(&dev->wait_frame);
init_waitqueue_head(&dev->wait_stream);

dev->em28xx_write_regs = em28xx_write_regs;
dev->em28xx_read_reg = em28xx_read_reg;
Expand Down
6 changes: 6 additions & 0 deletions drivers/media/video/em28xx/em28xx.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -258,6 +258,7 @@ struct em28xx {
int vscale; /* vertical scale factor (see datasheet) */
int interlaced; /* 1=interlace fileds, 0=just top fileds */
int type;
unsigned int reader:1;

unsigned long hash; /* eeprom hash - for boards with generic ID */
unsigned long i2c_hash; /* i2c devicelist hash - for boards with generic ID */
Expand Down Expand Up @@ -294,6 +295,11 @@ struct em28xx {
int (*em28xx_read_reg_req) (struct em28xx * dev, u8 req, u16 reg);
};

struct em28xx_fh {
struct em28xx *dev;
unsigned int reader:1;
};

/* Provided by em28xx-i2c.c */

void em28xx_i2c_call_clients(struct em28xx *dev, unsigned int cmd, void *arg);
Expand Down

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