Bug 79350

Summary: "ata" unrequested increase in xDMAx speed due to channel reset
Product: Base System Reporter: Murray Baker <murray_baker>
Component: i386Assignee: freebsd-i386 (Nobody) <i386>
Status: Closed FIXED    
Severity: Affects Only Me    
Priority: Normal    
Version: Unspecified   
Hardware: Any   
OS: Any   

Description Murray Baker 2005-03-30 03:50:02 UTC 
      Various cd related operations cause an ata channel reset. This is
a problem if atacontrol has previously been used to set a slower xDMAx
speed, the original detected higher speed not working properly.

Attempting to mount_cd9660 a defective or incompatible media can do
this. So will "atacontrol reinit" or "camcontrol reset".

How-To-Repeat:       Can be demonstrated as follows...
atacontrol mode 1
Master = UDMA33
Slave  = UDMA66
atacontrol mode 1 UDMA33 UDMA33
Master = UDMA33
Slave  = UDMA33
camcontrol reset 1              (or atacontrol reinit 1)
Reset of bus 1 was successful
atacontrol mode 1
Master = UDMA33
Slave  = UDMA66
Comment 1 Søren Schmidt freebsd_committer freebsd_triage 2006-01-05 00:42:37 UTC 
State Changed
From-To: open->closed

A channel reset clears all knowledge of the device, hence it cannot  
(and should not) remeber any changes done to it prior to a reset.