On Tue, 23 Mar 2004, Jonathan Woithe wrote:
> > Could you add exactly same initialization sequence to
> > alsa-oss/test/testoss.c code? So we can debug easily the problem here.
>
> Sorry, I couldn't see where this would fit in in this file - testoss.c seems
> more like it's testing the oss redirector though. The bug I'm seeing is in
> software which uses the oss emulation layer directly (that is, it accesses
> /dev/dsp with no knowledge of ALSA).
This code uses also directly the OSS layer.
> This program's output with ALSA when XX==16 (with alsa debug mode preventing
> divide by zero):
> params: fragments=2 fragstotal=2 fragsize=32768 bytes=65536
The reason for oops is simple: The period is too much big to store
resolution in the 32-bit value. The bellow patch fixed the oops, but
it's still not perfect solution (PCM slave timer resolution will be broken
in this case):
Index: pcm_timer.c
===================================================================
RCS file: /cvsroot/alsa/alsa-kernel/core/pcm_timer.c,v
retrieving revision 1.6
retrieving revision 1.7
diff -u -r1.6 -r1.7
--- pcm_timer.c 13 Aug 2002 16:13:34 -0000 1.6
+++ pcm_timer.c 23 Mar 2004 08:37:09 -0000 1.7
@@ -32,9 +32,9 @@
*/
/* Greatest common divisor */
-static int gcd(int a, int b)
+static unsigned long gcd(unsigned long a, unsigned long b)
{
- int r;
+ unsigned long r;
if (a < b) {
r = a;
a = b;
@@ -49,7 +49,7 @@
void snd_pcm_timer_resolution_change(snd_pcm_substream_t *substream)
{
- unsigned int rate, mult, fsize, l;
+ unsigned long rate, mult, fsize, l;
snd_pcm_runtime_t *runtime = substream->runtime;
mult = 1000000000;
@@ -67,7 +67,11 @@
mult /= 2;
rate /= 2;
}
- snd_assert(rate != 0, return);
+ if (rate == 0) {
+ snd_printk(KERN_ERR "pcm timer resolution out of range (rate = %u,
period_size = %lu)\n", runtime->rate, runtime->period_size);
+ runtime->timer_resolution = -1;
+ return;
+ }
runtime->timer_resolution = mult * fsize / rate;
}
Jaroslav
-----
Jaroslav Kysela <[EMAIL PROTECTED]>
Linux Kernel Sound Maintainer
ALSA Project, SuSE Labs
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