[vox-tech] DVD issues

[Jonathan Stickel]

dylan wrote:
> Hi everyone,
> 
> I was recently messing about with DVD playback on linux, and was less than
> impressed with the quality- i.e. playback was at about 75% speed. after some
> googling i came to the conclusion that I had 2 options: 1 get a better video
> card  or 2, fix the DMA settings on the drive with hdparm... (the xv
> extension to X11 was already installed)
> 
> 
> the initial output from hdparm was as follows:
> linux:/var/log # hdparm /dev/dvd
> ---------------------
> /dev/dvd: 
>  HDIO_GET_MULTCOUNT failed: Invalid argument
>  IO_support   =  0 (default 16-bit)
>  unmaskirq    =  0 (off)
>  using_dma    =  0 (off)
>  keepsettings =  0 (off)
>  readonly     =  1 (on)
>  readahead    = 256 (on)
>  HDIO_GETGEO failed: Invalid argument
> ---------------------
> 
> i tried a couple of combinations of turning on DMA, as well as toggling the
> other settings. Any setting other than the default lead to a non-functioning
> DVD drive, and the following lines in /var/log/messages:
> ---------------------
> Aug 10 22:40:00 linux kernel: hdd: drive_cmd: status=0x51 { DriveReady
> SeekComplete Error }
> Aug 10 22:40:00 linux kernel: hdd: drive_cmd: error=0x04Aborted Command
> ---------------------
> 
> I have ordered a new video card for this machine, as the integrated video is
> awful. perhaps this will solve my problems. however, is it normal for a
> modern DVD drive like this one refuse to accept DMA transfers?
> 

How "modern" is it?  Booting up a few machines lately, I've seen a 
kernel message about the cdrom (admittedly old) being "blacklisted" and 
therefore dma was set to be off.

On another list, I recently saw a long thread about dma not working for 
a dvdrw drive.  The problem ended up being an improper kernel 
configuration, specifically the motherboard chipset drivers were not 
compiled into the kernel. From what I understand, hdparm is unnecessary 
other than a diagnostic tool as long as the kernel is correctly compiled 
for your hardware.

HTH,
Jonathan