Date: Thu, 20 Apr 2006 06:47:00 +0800 From: Ariff Abdullah <ariff@FreeBSD.org> To: hartzell@alerce.com Cc: freebsd-multimedia@FreeBSD.org Subject: Re: Odd code in sound/pcm/channel.c, help with PR? Message-ID: <20060420064700.48c63e27.ariff@FreeBSD.org> In-Reply-To: <17477.44637.316536.583639@satchel.alerce.com> References: <17477.44637.316536.583639@satchel.alerce.com>
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[-- Attachment #1 --] On Tue, 18 Apr 2006 20:28:29 -0700 George Hartzell <hartzell@alerce.com> wrote: > > I'm trying to get some traction and get sound to work on my ASUS > A8V-MX. I keep ending up with > > pcm0:play:0::dsp0.0: play interrupt timeout, channel dead > > on my console. > > I've filed a PR with more details: > > http://www.freebsd.org/cgi/query-pr.cgi?pr=95949 > > I've been looking around, trying to understand what might be going > on. I came across the following piece of code in > /usr/src/sys/device/sound/pcm/channel.com, around line 320 > > timeout = (hz * sndbuf_getblksz(bs)) / (sndbuf_getspd(bs) * > sndbuf_getbps(bs)); if (timeout < 1) > timeout = 1; > timeout = 1; > ret = chn_sleep(c, "pcmwr", timeout); > if (ret == EWOULDBLOCK) { > count -= timeout; > ret = 0; > } else if (ret == 0) > count = hz; > > It's funny that it goes to the trouble to figure out a timeout value > then seems to unconditionally set it to 1. > It is indeed, funny :) > Removing that line doesn't seem to fix my problem, but it still > seems weird. > > > And, while I've got your attention, can anyone suggest where I might > look to understand why the buffer doesn't seem to be being emptied? > It's because the hardware DMA pointer is being lazy and need a good spank on its face. Replace your sys/dev/sound/pci/via8233.c with: http://people.freebsd.org/~ariff/test/via8233.c As usual, recompile your kernel, or just the modules. If this doesn't work, I still have few more other tricks. Coincidently, I'm currently investigating DMA incoherency within few drivers, notably this and few others. -- Ariff Abdullah FreeBSD [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.3 (FreeBSD) iD8DBQFERr3nlr+deMUwTNoRAtCBAJ9CzYMVQc7O/9g7mwgwqyfQWjzdlwCfdGD2 qbLMKeUeqB0fSx/ZRjxiOqo= =tt29 -----END PGP SIGNATURE-----
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