Date: Sun, 06 Dec 1998 20:57:43 -0600 From: David Kelly <dkelly@hiwaay.net> To: multimedia@FreeBSD.ORG Subject: Crystal Semiconductor and PCM driver question. Message-ID: <199812070257.UAA27446@n4hhe.ampr.org>
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In the continuing saga of my awful-sounding AOpen AW37 not-Pro, have been studying Luigi's PCM source code and the Crystal Semiconductor documentation for the CS4235 chip. Have not found where/if the pcm driver invokes the calibrate mode implemented in register 9, bits D3 and D4. Actually I'm fairly certain the hardware doesn't get calibrated. Register definition on page 36, How To Calibrate on page 67. If pcm is forced to detect the card as a SB Pro, it sounds fine. Possibly in SB mode Crystal Semiconductor sneaks in a calibrate? Considering I'm the one that has the problem and can replicate it, have been studying the code looking for the appropriate place to calibrate. mss_attach() in ad1848.c looks like a good place as the calibration routine doesn't need to be run but once per reset and takes time. Was thinking of using mss_detect() but my pnp-detected card doesn't appear to use that routine as there is no mss_detect output in dmesg while there is mss_attach(): Probing for PnP devices: CSN 1 Vendor ID: CSCd925 [0x25d9630e] Serial 0xffffffff Comp ID: @@@0000 [0x00000000] mss_attach <CS4235>1 at 0x530 irq 5 dma 1:3 flags 0x13 pcm1 (CS423x/Yamaha <CS4235> sn 0xffffffff) at 0x530-0x537 irq 5 drq 1 flags 0x13 on isa Because the calibration can take time and could possibly fail to complete in a reasonable amount of time, I presume the DELAY() routine also used by mss_detect() is safe to use? Or is there a better choice? -- David Kelly N4HHE, dkelly@nospam.hiwaay.net ===================================================================== The human mind ordinarily operates at only ten percent of its capacity -- the rest is overhead for the operating system. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-multimedia" in the body of the message
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