Re: How to change DVD-ROM speed?

From: Jeffrey W. Baker (
Date: Thu Jun 28 2001 - 01:42:43 EST

On Wed, 27 Jun 2001, Jens Axboe wrote:

> On Wed, Jun 27 2001, Jeffrey W. Baker wrote:
> >
> > I will be happy to :) Should I hang conditional code off the existing
> > ioctl (CDROM_SELECT_SPEED, ide_cdrom_select_speed) or use a new one?
> Excellent. I'd say use the same ioctl if you can, but default to using
> SET_STREAMING for DVD drives.

Hrmm, ah, hrmm. Perhaps I need a little help with this one :)

Just for testing, I modified cdrom_select_speed in ide-cd.c to use SET
STREAMING. Working from the Fuji spec, I created a 28-byte buffer, set
the starting lba to 0, the ending lba to 0xffffffff, the read speed to
0x000000ff, and the read time to 0x000000ff, expecting a resulting speed
of 1KB/ms or 1000KB/s[1]. I assign the buffer to pc.buffer and send it on
its way to cdrom_queue_packet_command().

The result is:

CDROM_SELECT_SPEED failed: Input/output error
hdc: status timeout: status 0x80 { Busy }
hdc: DMA disabled
hdc: ATAPI reset complete

Am I barking up the wrong tree? Do I need to use a different function,
or a generic command instead of a packet command?


[1] Interesting that there appears to be enough room in the spec for a
drive transferring 2^32 * 1000 KB/s.

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This archive was generated by hypermail 2b29 : Sat Jun 30 2001 - 21:00:18 EST