hdpvr: fix interrupted recording

Ryley, Keith, can you test this one more time and if it works reply with a 'Tested-by' tag that I can add to the patch?

Thanks!

Hans

This issue was reported by Ryley Angus:

<quote>
I record from my satellite set top box using component video and optical audio input. I basically use "cat /dev/video0 > ~/video.ts” or use dd. The box is set to output audio as AC-3 over optical, but most channels are actually output as stereo PCM. When the channel is changed between a PCM channel and (typically to a movie channel) to a channel utilising AC-3, the HD-PVR stops the recording as the set top box momentarily outputs no audio. Changing between PCM channels doesn't cause any issues.

My main problem was that when this happens, cat/dd doesn't actually exit. When going through the hdpvr driver source and the dmesg output, I found the hdpvr driver wasn't actually shutting down the device properly until I manually killed cat/dd.

I've seen references to this issue being a hardware issue from as far back
as 2010: http://forums.gbpvr.com/showthread.php?46429-HD-PVR-drops-recording-on-channel-change-Hauppauge-says-too-bad .

I tracked my issue to the file hdpvr-video.c. Specifically:
"if (wait_event_interruptible(dev->wait_data, buf->status = BUFSTAT_READY)) {" (line ~450). The device seems to get stuck waiting for the buffer to become ready. But as far as I can tell, when the channel is changed between a PCM and AC-3 broadcast the buffer status will never actually become ready. </quote>

Angus provided a hack to fix this, which I've rewritten.

Signed-off-by Hans Verkuil <[email protected]>

Reported-by Ryley Angus <[email protected]>

---
drivers/media/usb/hdpvr/hdpvr-video.c | 20 +++++++++++++++++---

1 file changed, 17 insertions(+), 3 deletions(-)

drivers/media/usb/hdpvr/hdpvr-video.c +17 -3

index 0500c417..44227da 100644
@@ -454,6 +454,8 @@ static ssize_t hdpvr_read(struct file *file, char __user *buffer, size_t count,
 
       if (buf->status != BUFSTAT_READY &&
           dev->status != STATUS_DISCONNECTED) {
+            int err;
+
           /* return nonblocking */
           if (file->f_flags & O_NONBLOCK) {
               if (!ret)

@@ -461,11 +463,23 @@ static ssize_t hdpvr_read(struct file *file, char __user *buffer, size_t count,
               goto err;
           }
 
-            if (wait_event_interruptible(dev->wait_data,
-                          buf->status == BUFSTAT_READY)) {
-                ret = -ERESTARTSYS;
+            err = wait_event_interruptible_timeout(dev->wait_data,
+                          buf->status == BUFSTAT_READY,
+                          msecs_to_jiffies(3000));
+            if (err < 0) {
+                ret = err;
               goto err;
           }
+            if (!err) {
+                v4l2_dbg(MSG_INFO, hdpvr_debug, &dev->v4l2_dev,
+                    "timeout: restart streaming\n");
+                hdpvr_stop_streaming(dev);
+                err = hdpvr_start_streaming(dev);
+                if (err) {
+                    ret = err;
+                    goto err;
+                }
+            }
       }
 
       if (buf->status != BUFSTAT_READY)

Signature · 1 line

2.0.0.rc0