diff options
| -rw-r--r-- | drivers/staging/comedi/comedi_fops.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/staging/comedi/comedi_fops.c b/drivers/staging/comedi/comedi_fops.c index f341421f1644..bd124815c06a 100644 --- a/drivers/staging/comedi/comedi_fops.c +++ b/drivers/staging/comedi/comedi_fops.c @@ -2262,7 +2262,7 @@ static unsigned int comedi_poll(struct file *file, poll_table *wait) unsigned int mask = 0; struct comedi_file *cfp = file->private_data; struct comedi_device *dev = cfp->dev; - struct comedi_subdevice *s; + struct comedi_subdevice *s, *s_read; mutex_lock(&dev->mutex); @@ -2272,6 +2272,7 @@ static unsigned int comedi_poll(struct file *file, poll_table *wait) } s = comedi_file_read_subdevice(file); + s_read = s; if (s && s->async) { poll_wait(file, &s->async->wait_head, wait); if (!s->busy || !comedi_is_subdevice_running(s) || @@ -2284,7 +2285,8 @@ static unsigned int comedi_poll(struct file *file, poll_table *wait) if (s && s->async) { unsigned int bps = comedi_bytes_per_sample(s); - poll_wait(file, &s->async->wait_head, wait); + if (s != s_read) + poll_wait(file, &s->async->wait_head, wait); comedi_buf_write_alloc(s, s->async->prealloc_bufsz); if (!s->busy || !comedi_is_subdevice_running(s) || !(s->async->cmd.flags & CMDF_WRITE) || |