From: Reza Naima <reza@reza.net>
To: Kernel List <linux-kernel@vger.kernel.org>
Subject: i810_audio bug (?)
Date: Wed, 17 Sep 2003 03:42:37 -0700 [thread overview]
Message-ID: <20030917104237.GB21397@boom.net> (raw)
When I pass audio_samplerate = 32000 to
ioctl(afd, SNDCTL_DSP_SPEED, &audio_samplerate)
it changes my audio_sample rate from 32000 to 31627.
Now, this is causing problems with my downstream apps so I did some
investigating. Looking into i810_set_adc_rate() in i810_audio.c,
there is some wierd math going on..
1) first, the original rate (32000) is converted to a new rate ..
rate = (rate * clocking)/48000
where clocking, in my case, is 48566.
2) this new value is fed into newrate=ac97_set_adc_rate() which returns
the orignal sampling rate value (32000). This number is then modified
by the ratio
dmabuf->rate = newrate * 48000 / clocking.
3) This results in the value 31627 that I'm seeing. Now, is this the
actual sample rate, or some internal value used to generate a 32000kbps
sample rate? If so, is it perhaps a bug that dmabuf->rate is being
returned rather than newrate?
Thanks,
-Reza
next reply other threads:[~2003-09-17 10:42 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-09-17 10:42 Reza Naima [this message]
2003-09-17 13:22 ` Alan Cox
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