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From: Mike Pritchard <mpp>
Message-Id: <199702171631.IAA25480@freefall.freebsd.org>
Subject: Re: kern/2305 (buggy IDE controller)
To: freebsd-bugs
Date: Mon, 17 Feb 1997 08:31:16 -0800 (PST)
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Does anyone who works on the IDE code feel like implementing a workaround
for this chipset?  If not, I'm going to go ahead and close this PR.


>Number:         2305
>Category:       kern
>Synopsis:       system hangs with second Ide controller
>Confidential:   no
>Severity:       critical
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sat Dec 28 04:10:01 PST 1996
>Last-Modified:  Wed Jan  1 03:50:02 PST 1997
>Originator:     Wolfgang Helbig
>Organization:
>Release:        FreeBSD 3.0-CURRENT i386
>Environment:

	Processor:	i486DX2
 	Motherboard: 	UM8810P AIO
	Chipsets:    	UMC UM8881 (Host Bridge)
			UMC UM8886 (ISA Brigde Controller)
			CMD PCIO640B (PCI Bus IDE Controller)
 	BIOS:		Phoenix - BIOS
	Disks:		Conner Peripherals 850 MB CFS850A
			Seagate 1275 MB ST31276A		
	CD-ROM:		Mitsumi ATAPI FX400
	Software:	Generic Kernel FreeBSD 2.1.5
		        Generic Kernel FreeBSD 2.2 Alpha
		        Kernel FreeBSD - current (22. Dec )
>Description:

        Whenever wdc1 and wdc0 are used concurrently (copying one 
        file from a disk connected to wdc1 to a disk connected to
        wdc0) the system hangs after about 2 seconds.	

>How-To-Repeat:

 	Attach one disk as master to wdc0 the other as master to
        wdc1 and copy a big file from one disk to the other.	
	OR:
	Attach one disk as master to wdc2, the other as master to
	wdc0 and the CD-ROM as slave to wdc0. Try to install
	from CD-ROM to the disk on wdc2. (FreeBSD 2.1.5-boot.flp)
	Everything works fine till the binaries are installed. The
	system hangs.

>Fix:
  	Attach both disks to wdc0 and forget the CD-ROM.
>Audit-Trail:

From: Helbig@MX.BA-Stuttgart.De
To: freebsd-gnats-submit@freebsd.org, wh@helbig.informatik.ba-stuttgart.de
Cc:  Subject: Re: kern/2305: system hangs with second Ide controller
Date: Wed, 1 Jan 1997 12:48:11 +0100 (MET)

 In the meantime I have been pointed to some URL's (thanks to everyone !)
 from which I learned that I have a "well known problem", the IDE-Controller
 CMD 640B, which just doesn't support concurrently use of both channels.
 Seems that other operating systems either don't use primary and secondary
 IDE port simultaneously (like DOS ...) or have an option to prevent this
 (like Linux).
 I wonder why it's worthwhile to implement a workaround for this 
 hardware flaw in the FreeBSD-Kernel.
 
 The URLS are: 
 	http://thef-nym.sci.kun.nl/cgi-pieterh/atazip/atafq-3.html#ss3.2
 	http://www.phyttp://www.physics.ohio-state.edu/~jrdemers/ibm/eide.txt
 
 Of the three 640B-flaws mentioned in the second URL only the third
 seems to apply to my configuration. (lucky me!):
 	Does not support simultaneous I/O on primary and secondary EIDE ports.
 
 If someone patched the wd-controller to avoid simultaneous I/O please let
 me know!
 
 Happy New Year,
 						Wolfgang Helbig
-- 
Mike Pritchard
mpp@FreeBSD.org
"Go that way.  Really fast.  If something gets in your way, turn"