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authorMauro Carvalho Chehab <mchehab@infradead.org>2007-11-11 01:13:49 -0300
committerMauro Carvalho Chehab <mchehab@infradead.org>2008-01-25 19:02:07 -0200
commit9e31ced888d1ca49ec5be51ef295e3ce994366c4 (patch)
tree23593504461672ce1f6ef405171b859c42404019
parenta225452ef80a7bd894fd2dfd01a4973d444152f4 (diff)
V4L/DVB (6584): Fix read() method
Backport read() fixes from Markus Rechberger. Signed-off-by: Mauro Carvalho Chehab <mchehab@infradead.org>
-rw-r--r--drivers/media/video/em28xx/em28xx-video.c30
-rw-r--r--drivers/media/video/em28xx/em28xx.h2
2 files changed, 24 insertions, 8 deletions
diff --git a/drivers/media/video/em28xx/em28xx-video.c b/drivers/media/video/em28xx/em28xx-video.c
index f0191779a8e..8a4d221a4fe 100644
--- a/drivers/media/video/em28xx/em28xx-video.c
+++ b/drivers/media/video/em28xx/em28xx-video.c
@@ -416,6 +416,9 @@ em28xx_v4l2_read(struct file *filp, char __user * buf, size_t count,
struct em28xx_fh *fh = filp->private_data;
struct em28xx *dev = fh->dev;
+ /* FIXME: read() is not prepared to allow changing the video
+ resolution while streaming. Seems a bug at em28xx_set_fmt
+ */
if (unlikely(res_get(fh) < 0))
return -EBUSY;
@@ -498,25 +501,36 @@ em28xx_v4l2_read(struct file *filp, char __user * buf, size_t count,
mutex_unlock(&dev->lock);
return -ENODEV;
}
+ dev->video_bytesread = 0;
}
f = list_entry(dev->outqueue.prev, struct em28xx_frame_t, frame);
- spin_lock_irqsave(&dev->queue_lock, lock_flags);
- list_for_each_entry(i, &dev->outqueue, frame)
- i->state = F_UNUSED;
- INIT_LIST_HEAD(&dev->outqueue);
- spin_unlock_irqrestore(&dev->queue_lock, lock_flags);
-
em28xx_queue_unusedframes(dev);
if (count > f->buf.length)
count = f->buf.length;
- if (copy_to_user(buf, f->bufmem, count)) {
- mutex_unlock(&dev->lock);
+ if ((dev->video_bytesread + count) > dev->frame_size)
+ count = dev->frame_size - dev->video_bytesread;
+
+ if (copy_to_user(buf, f->bufmem+dev->video_bytesread, count)) {
+ em28xx_err("Error while copying to user\n");
return -EFAULT;
}
+ dev->video_bytesread += count;
+
+ if (dev->video_bytesread == dev->frame_size) {
+ spin_lock_irqsave(&dev->queue_lock, lock_flags);
+ list_for_each_entry(i, &dev->outqueue, frame)
+ i->state = F_UNUSED;
+ INIT_LIST_HEAD(&dev->outqueue);
+ spin_unlock_irqrestore(&dev->queue_lock, lock_flags);
+
+ em28xx_queue_unusedframes(dev);
+ dev->video_bytesread = 0;
+ }
+
*f_pos += count;
mutex_unlock(&dev->lock);
diff --git a/drivers/media/video/em28xx/em28xx.h b/drivers/media/video/em28xx/em28xx.h
index 3efc05d2df6..672880383de 100644
--- a/drivers/media/video/em28xx/em28xx.h
+++ b/drivers/media/video/em28xx/em28xx.h
@@ -260,6 +260,7 @@ struct em28xx {
int vscale; /* vertical scale factor (see datasheet) */
int interlaced; /* 1=interlace fileds, 0=just top fileds */
int type;
+ unsigned int video_bytesread; /* Number of bytes read */
unsigned long hash; /* eeprom hash - for boards with generic ID */
unsigned long i2c_hash; /* i2c devicelist hash - for boards with generic ID */
@@ -268,6 +269,7 @@ struct em28xx {
enum em28xx_dev_state state;
enum em28xx_stream_state stream;
enum em28xx_io_method io;
+
/* locks */
struct mutex lock;
spinlock_t queue_lock;