[PlanetCCRMA] Re: DVD playback not fluent

John Wheeler jdw27_42@hotmail.com
Fri Apr 11 05:15:02 2003

>Subject: Re: [PlanetCCRMA] DVD playback not fluent
>From: Mike Artis <mike@techead.com>
>To: Alex Timmer <mijn_troep@yahoo.com>
>Cc: planetccrma@ccrma.Stanford.EDU
>Date: 09 Apr 2003 16:44:24 -0400
>It may also not be video drivers causing the problem.  Have you checked
>to see whether DMA is enabled on the DVD drive?
>Try hdparm -d /dev/dvd to see if it's enabled.  If not, it will really
>help latency if you enable it by issuing this command: hdparm -d 1
>Read the hdparm man page for more options you can add to set ide disk

When I tried "/sbin/hdparm -d 1 /dev/dvd" as a normal user, obviously I got 
the message:

setting using_dma to 1 (on)
HDIO_SET_DMA failed: Permission denied
using_dma    =  0 (off)

However, when I tried it as root, I got:

setting using_dma to 1 (on)
HDIO_SET_DMA failed: Operation not permitted
using_dma    =  0 (off)

Since the message isn't the same as for a normal user, I assume it's a 
different problem.  Is this a hardware problem?  Is there an easy fix?

My DVD playback is reasonably smooth, just with momentary glitches, so if 
there's a possibilty of breaking anything, I'll just live with it.  It's 
just obnoxious that DVD playback is smoother under Windows 98.  (Of course, 
in exchange occasionally the DVD player hangs Windows hard enough to require 
a hard reset.)


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