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Date: Sat, 13 Jul 2002 18:34:25 -0600
From: Erik Andersen <andersen@codepoet.org>
To: Olivier Galibert <galibert@pobox.com>, linux-kernel@vger.kernel.org
Subject: Re: IDE/ATAPI in 2.5
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On Sat Jul 13, 2002 at 12:53:46PM -0400, Olivier Galibert wrote:
> On Fri, Jul 12, 2002 at 11:40:58PM -0600, Erik Andersen wrote:
> > If you would throw away crdrecord's desire to do its own private
> > SCSI bus scanning
> 
> CDROM_SEND_PACKET sounds nice, but do you have a way to:
> 1- Find all cdrom-ish devices in the system
> 2- Find if a given device is cdrom-ish
> 
> By cdrom-ish, I mean cdrom, dvdrom, cd writer, dvd writer or a
> combination.
> 
> Point 1 is necessary to be a minimum user-friendly, point 2 is
> necessary because you can't trust users :-)

Well, one way would be to scan for them directly, i.e.:
    for i in /dev/hd* ; do 
	ioctl(fd, HDIO_GET_IDENTITY, &ident);
	if (!(ident.config & 0x4000) && ((ident.config & 0x1f00) >> 8)==5) {
	    /* Got an ATAPI cdrom drive */
	}
    for i in /dev/scd* ; do
	open ($i, O_RDONLY|O_NONBLOCK)) < 0) {
	    /* Got a SCSI cdrom drive */
	}
  
Of course making user space do this is pretty lame.  But we
have a much better way.  Each cdrom device registers with the
uniform cdrom driver, which can easily assign each registered
cdrom device a major and minor.  That scanning for cdroms would
be as simple as
    for i in /dev/cdrom* ; do
	open ($i, O_RDONLY|O_NONBLOCK)) < 0) {
	    /* Found a cdrom drive */
	}
    
 -Erik

--
Erik B. Andersen             http://codepoet-consulting.com/
--This message was written using 73% post-consumer electrons--
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