svn commit: r235007 - stable/9/sys/dev/pci

[Warner Losh]

On May 4, 2012, at 10:26 AM, Hans Petter Selasky wrote:

> On Friday 04 May 2012 18:14:16 John Baldwin wrote:
>> On Friday, May 04, 2012 11:38:47 am Hans Petter Selasky wrote:
>>> Author: hselasky
>>> Date: Fri May  4 15:38:47 2012
>>> New Revision: 235007
>>> URL: http://svn.freebsd.org/changeset/base/235007
>>> 
>>> Log:
>>>  MFC r233662, r233677 and r233678:
>>> 
>>>  Writing zero to BAR actually does not disable it and
>>>  it is even harmful as hselasky found out.  Historically,
>>>  this code was originated from (OLDCARD) CardBus driver and later leaked
>>>  into PCI driver when CardBus was newbus'ified and refactored with PCI
>>>  driver. However, it is not really necessary even for CardBus.
>> 
>> FYI, I've got one bug report on HEAD where these changes broke a machine's
>> ATA controller.
> 
> Have you considered adding code to disable the I/O or memory range instead of 
> writing 0 to the bar in this case?

I tried that once upon a time, but was problematical with some bridges that had BARs at non-standard locations that needed the I/O or MEM bit set in order to work...

Warner