Date: Mon, 20 Sep 1999 10:52:10 +0200 (CEST) From: "Dave J. Boers" <djb@Wit389306.student.utwente.nl> To: freebsd-hackers@freebsd.org Subject: reading from pcm device Message-ID: <199909200852.KAA17525@Wit389306.student.utwente.nl>
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I have been working on a small program to record from the microphone of my SB16PnP using the pcm driver. Could anyone explain to me why I get a kernel panic if I read() 8192 bytes at a time (in 8 bit audio, single channel, 41k4 Hz)? The kernel panic message is (from notes) panic: feed_root: uiomove failed mp_lock=00000001; cpuid=0; lapci.id=00000000 boot() called on cpu#0 The panic doesn't occur if I read only 256 bytes at a time, but if I also make writes in between reading blocks (writes to stdout, for example, using write() to write the block that's just been read), the problem also happens with 256 bytes blocks. I know that the problem doesn't occur for write()'s to the audio device, since, for example, WSoundServer uses a blocksize of 8192 bytes and it works fine for me. This has been happening on a -current machine running SMP on ABIT BP6 with dual Celeron. The test program runs as an ordinary user, of course. The processors are overclocked, but bus speed is still 66MHz and system runs fine otherwise. Eager for your comments, Dave Boers. Dave J. Boers Graduate student of Theoretical Physics ------------------------------------------------------------------------- Primary email address: djb@relativity.student.utwente.nl Please DO NOT use d.j.boers@student.utwente.nl because it won't be read! ------------------------------------------------------------------------- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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