Date: Wed, 24 Aug 2005 12:47:51 +0200 From: Jan Stary <hans@stare.cz> To: freebsd-multimedia@freebsd.org Subject: audio chip properties Message-ID: <20050824104751.GA60896@ns.stare.cz>
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Hello, in an attempt to fully understand my SoundBlaster AEW64 card, running on FreeBSD 5.4-RELEASE-p6, I have the following question: after kldloading snd_sbc and snd_sb16, I get # kldload snd_sbc sbc0: <Creative SB AWE64> at port 0x388-0x38b,0x330-0x331,0x220-0x22f irq 5 drq 5,1 on isa0 # kldload snd_sb16 pcm0: <SB16 DSP 4.16> on sbc0 $ cat /dev/sndstat FreeBSD Audio Driver (newpcm) Installed devices: pcm0: <SB16 DSP 4.16> at io 0x220 irq 5 drq 1:5 bufsz 4096d kld snd_sb16 (1p/1r/1v channels duplex default) I wonder what exactly do the fields mean; please correct me where I am wrong: it seems to me that a) a SB16 DSP 4.16 audio chip was found b) at address 0x220 c) it wants to send its interrupts via irq channel 5 and the kernel agrees to that. d) the "DMA channel number" (man device.hints) is 1 or 5? What exactly does "drq 1:5" mean? Is this the "secondary DMA channel" which man snd_sbc speaks about? If so, what is "secondary" about it, ie what is the "primary DMA channel"? e) the DMA buffer is 4096 bytes; what does the "d" stand for? f) the device is driven by the snd_sb16 module g) it has one playback channel, one record channel, and one virtual channel; it is capable of full duplex (ie, can playback and record at the same time); it is the default audio device. Thanks for any hints Jan
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