> On 11 March 2003, Guido van Rossum said:
> > Great! I wonder if you have any thoughts on why running
> > test_ossaudiodev hangs when run on Linux Red Hat 7.3? I'm currently
> > using a 2.4.18-24.7.x kernel. I have no idea what other info would be
> > useful to debug this.
[Greg]
> The most obvious cause is that some other process has the audio device
> open, and your audio {hardware, device driver} only allows one at a
> time.
Hm, but I *do* hear some sound coming out of the speaker: a quiet,
sped-up squeaky version of the "nobody expects the spanish
inquisition" soundclip that test_linuxaudiodev also used to play.
(The latter now crashes for me with "linuxaudiodev.error: (0,
'Error')".)
> If you're running one of those newfangled GUI environments like KDE or
> GNOME, it's quite likely that the esound or aRTSd (however you spell it)
> daemon started when you logged in, and is thus blocking all access to
> your /dev/dsp. This sucks, but IMHO it's not ossaudiodev's job to know
> about esound and similar.
>
> One way to test this is to take your system down to single-user (or at
> least a console-only, no-X11 runlevel) and then try running
> test_ossaudiodev.
I tried this at runlevel 1, and the symptoms are identical: some
squeaks, then it hangs.
> Hmmm, it looks like calling open() with O_NONBLOCK helps. I know this
> does *not* affect later read()/write() -- there's a special ioctl() for
> non-blocking read/write -- but it *does* appear to fix blocking open().
> At least for me it turned a second open() attempt on the same device
> from "hang" to "IOError: [Errno 16] Device or resource busy:
> '/dev/dsp2'".
>
> Try this patch; if it works I'll check it in:
>
> --- Modules/ossaudiodev.c 10 Mar 2003 03:17:06 -0000 1.24
> +++ Modules/ossaudiodev.c 11 Mar 2003 15:56:24 -0000
> @@ -131,7 +131,7 @@
> basedev = "/dev/dsp";
> }
>
> - if ((fd = open(basedev, imode)) == -1) {
> + if ((fd = open(basedev, imode|O_NONBLOCK)) == -1) {
> PyErr_SetFromErrnoWithFilename(PyExc_IOError, basedev);
> return NULL;
> }
>
> test_ossaudiodev.py will still need fixing to handle the EBUSY error,
> but at least this should prevent hanging on open().
Yes, it fixes the hang. Please check it in!
The sample is still played at too high a speed, but maybe that's
expected?
--Guido van Rossum (home page: http://www.python.org/~guido/)
RetroSearch is an open source project built by @garambo | Open a GitHub Issue
Search and Browse the WWW like it's 1997 | Search results from DuckDuckGo
HTML:
3.2
| Encoding:
UTF-8
| Version:
0.7.4