>Number:         36819
>Category:       install
>Synopsis:       Can not mount cdrom after boot of install cd
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    install-manager
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Wed Aug 22 02:20:00 +0000 2007
>Originator:     Joseph Sarkes
>Release:        NetBSD 4.0_BETA2
>Organization:
	
>Environment:
i386 amd64
	
	
System: NetBSD amd64x2 4.0_BETA2 NetBSD 4.0_BETA2 (GENERIC) #0: Tue Aug 21 01:32:00 PDT 2007 builds@wb28:/home/builds/ab/netbsd-4/amd64/200708200002Z-obj/home/builds/ab/netbsd-4/src/sys/arch/amd64/compile/GENERIC amd64
Architecture: x86_64
Machine: amd64
>Description:
	The cdrom can not be mounted after booting from bios. There
	is a complaint of io error on the cdrom device, where the
	device is KNOWN to work under windows and linux.
	Under some unknown circumstances, sometimes by doing dd
	commands to the device it can be caused to finally downgrade
	the ide bus speed and it works fine.
	This is using a current high speed dvd-ram drive with the 
	original ide cable installed from an earlier lower performance
	dvd drive.  
	
>How-To-Repeat:
	Install a NEW high speed ide dvd-rw drive in an older system
	using a 40 wire ide cable. If the drive is detected as an
	ata-66 capable device it will try to run at that speed, and
	upon io errors (inevitable with the 40 pin cable) it will not
	downgrade to slower speeds to the point where it will work.
	
>Fix:
	This used to work, and broke around the release of 3.1.
	Initial quick fix is to replace the ide cable with an 80
	wire high speed ribbon, which fixes the problem. However 
	the cable should be detected, and the unit should be run
	at a lower operational speed. Windows and Linux work fine,
	so there is no reason that NetBSD should have an io error
	that doesn't fix itself automagically. A more intuitive
	warning that one should replace the cable with an 80 wire
	one, along with automatic lowering of speed would fix it.
	Otherwise a remark somewhere in the install docs to ensure
	that the dvd-rw has a high speed cable installed on it (many
	computers come with only a 40 pin cable for the cdrom)

	

>Unformatted:
 		200708200002Z and many earlier versions