Date: Thu, 8 Jan 2004 19:55:05 -0500 From: Martin Cracauer <cracauer@cons.org> To: hardware@freebsd.org Subject: ATA and readahead on DVD drive, ATA_C_F_ENAB_RCACHE Message-ID: <20040108195505.A15849@cons.org>
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Hi, Soeren, other ATA people, are there any readahead options or other buffering that I can enable in the ATA driver, for a DVD drive? I see there is a call like this in the source: if (ata_command(atadev, ATA_C_SETFEATURES, 0, 0, ATA_C_F_ENAB_RCACHE, ATA_WAIT_INTR)) ata_prtdev(atadev, "enabling readahead cache failed\n"); Can I trigger that call manually from userland? How can I know whether this call have been executed at all? Long story: On my FreeBSD-4.9 machine I cannot directly play DVDs, the drive is too slow (under FreeBSD), but only occasionally, as in hickups. I can watch DVDs fine with `mplayer -cache 8192`, which will buffer up 8 MB and then playing out of the buffer. However I would prefer to use Xine which doesn't have the buffer option and stutters every few seconds. I can proof that the long-term bandwidth of the drive is enough and that it is actally the drive that is the problem, because this works without stutter: play_title 1 1 | cstream -B 8m -c2 | xine - [ play_title is part of libdvdread and dumps the mpeg streamto stdout, cstream is a stream tool with buffering option ] The same hardware (CPU, Mainboard, IDE-Controller, DVD drive) played fine under Linux with the same version of xine. So I think it is a reasonable assumption that the difference here is that Linux buffers on the driver level (or in the drive) and FreeBSD does not. Hardware: - P3-based Celeron 1300 MHz - P2B mainboard - this drive is on the PIIX4 on-mainboard controller - 384 MB RAM - G-400 32 MB - acd0: DVD-ROM <JLMS XJ-HD165H> at ata0-slave UDMA33 - (full dmesg on http://wavehh.dyndns.org/tmp/dmesg.boot) On the other channel of the PIIX4 controller is a acd1: CD-RW <32X10> at ata1-master WDMA2 Could the presense of that be responsible for the problems on the first drive? Martin -- %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Martin Cracauer <cracauer@cons.org> http://www.cons.org/cracauer/ No warranty. This email is probably produced by one of my cats stepping on the keys. No, I don't have an infinite number of cats.
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