[linux-dvb] Help using DMX_SET_BUFFER_SIZE

[Florian Lohoff]

On Sat, Mar 01, 2008 at 12:20:05AM +0000, Andrea wrote:
> Hi,
> 
> I've tried to add an extra argument to gnutv to set the size of the dvb_ringbuffer via 
> DMX_SET_BUFFER_SIZE.
> 
> I have not really understood the difference between dvr and demux.
> It seems that gnutv uses the dvr to read from the DVB card and then copies the content to a file.
> 
> I call
> 
> int dvbdemux_set_buffer(int fd, int bufsize)
> {
> 	return ioctl(fd, DMX_SET_BUFFER_SIZE, bufsize);
> }
> 
> on the dvr (I think), but it does not make much of a change. The ioctl call returns success.
> I've printed a lot of debug output (adding a few dprintk) and this is what I see when I run gnutv.
> Now, I set the buffer to 1024 * 1024 which is nowhere in the log.
> I cannot see in the log the 2 functions (demux and dvr) handling this ioctl call:
> dvb_demux_do_ioctl and dvb_dvr_do_ioctl (I've added some printk as well).

In 2.6.25-rc3 the dvr kernel side looks like this:

1015         switch (cmd) {
1016         case DMX_SET_BUFFER_SIZE:
1017                 // FIXME: implement
1018                 ret = 0;
1019                 break;

i guess its clear why it doesnt make a difference ;)

Flo
-- 
Florian Lohoff                  flo at rfc822.org             +49-171-2280134
	Those who would give up a little freedom to get a little 
          security shall soon have neither - Benjamin Franklin
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