From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Herrenschmidt To: Henry Worth , Subject: Re: CDDA playback on Pismo (and other newer models) Date: Fri, 4 Aug 2000 14:57:50 +0200 Message-Id: <20000804125750.16864@mailhost.mipsys.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: owner-linuxppc-dev@lists.linuxppc.org List-Id: > >Using the ATAPI CD drivers there are underruns with significant >dropouts every couple of seconds. Various hdparms and cdparanoia >parms were tried with no significant change. These include various >transfers modes and cdparanoia's buffer (-n) and speed (-S) >parms and various data formats. Piping cdparanoia out to /dev/null >showed data rates of 46 sectors/sec at -S1, 65sps at -S8, and >133sps at -S12 and above (also the default and no significant >changes with different transfer modes and -n values). At the higher >speeds (>-S11) there is a high-level of continuous head-seek noise, >suggesting a lot of overruns and reseeks on the CD i/f side. > >Rebuilding the kernel to use SCSI generic devices with IDE SCSI >emulation produced much better, even usable, results. At startup >there are still a couple of dropouts in the first few seconds, >but after that the playback is clean across multiple tracks (even >with a concurrent kernel compile). Piping cdparanoia to /dev/null >shows data rates of 187sectors/sec at all -S settings (and default). >>From the the drive's spin-up sounds it seems to always be in >high-speed mode, but unlike the ATAPI driver, there is little >head movement noise. I think the problem is more with cdparanoia. I think it's more or less synchronous, it doesn't have a thread that collects datas while another outputs sounds. I've looked at cdparanoia sources some time ago, and I think and intermediate step of buffering is necessary. ** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/