i386/79272: "ata" detects and enables UDMA66 or UDMA100 with 40 wire cable

[Murray Baker]

>Number:         79272
>Category:       i386
>Synopsis:       "ata" detects and enables UDMA66 or UDMA100 with 40 wire cable
>Confidential:   no
>Severity:       non-critical
>Priority:       low
>Responsible:    freebsd-i386
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Mar 27 05:00:09 GMT 2005
>Closed-Date:
>Last-Modified:
>Originator:     Murray Baker
>Release:        5.3
>Organization:
>Environment:
5.3 standard or custom kernel, several different machines.
>Description:
      "ata" driver detects too high an xDMAx speed, several hw
combinations, 5.3-RELEASE. Incorrect cable identification?

1/ PCchips (SiS) P///-800 mobo, Pioneer DVD117, *40* wire cable, the
dvd is configured for UDMA66 (partially works, unreliable).

2/ Various socket 7 mobo, PCI card with CMD0649 chip, Maxtor D740X-6L
HDD (probably others also), *40* wire cable, hdd is configured for
UDMA100 (doesn't work).

(I have probably seen this on other hw combinations also.)

"atacontrol" can be used to reconfigure a dvd after booting. The worse
problem is hdd, trying to boot install media and do an install.
>How-To-Repeat:
      Same hw?
>Fix:
      
>Release-Note:
>Audit-Trail:
>Unformatted: