Date: Tue, 22 Jul 1997 03:14:44 +0930 (CST) From: Michael Smith <msmith@atrad.adelaide.edu.au> To: hasty@rah.star-gate.com (Amancio Hasty) Cc: hackers@FreeBSD.ORG, multimedia@FreeBSD.ORG, luigi@labinfo.iet.unipi.it Subject: Re: auto dma? Message-ID: <199707211744.DAA24577@genesis.atrad.adelaide.edu.au> In-Reply-To: <199707211657.JAA05307@rah.star-gate.com> from Amancio Hasty at "Jul 21, 97 09:57:51 am"
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Amancio Hasty stands accused of saying: > > luigi@labinfo.iet.unipi.it said: > > I am looking at Mike's idea of using DMA_AUTOMODE and a circular > > buffer, but unfortunately there are no support routines to read the > > current transfer status from the dma registers and I have to write > > them myself. This also means that the old sound driver probably did > > not really work very reliably, and explains why someone was reporting > > that pieces of sound were repeating multiple times. > > Does anyone know how to read the current number of bytes transferred in > in a dma transfer? > It will be kind of nice to know as a safe guard for cards which > occasionlly fail to generate an interrupt and yes I do have such a card > is the SB16... This was one of the reasons behind my suggesting that a 1/hz timeout should be running whenever the sound output is running. 1/128th of a second is a fairly short glitch for end-of-sample overrun. If you haven't got an answer by tomorrow (my time; mid-afternoon today your time) I will rummage my Intel databook and get back to you on that one. > Amancio -- ]] Mike Smith, Software Engineer msmith@gsoft.com.au [[ ]] Genesis Software genesis@gsoft.com.au [[ ]] High-speed data acquisition and (GSM mobile) 0411-222-496 [[ ]] realtime instrument control. (ph) +61-8-8267-3493 [[ ]] Unix hardware collector. "Where are your PEZ?" The Tick [[
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