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

[Hans Petter Selasky]

On Friday 04 May 2012 19:18:56 Warner Losh wrote:
> 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

If the size of the bar is a few megabytes, then moving it to location 0 is 
definitely wrong. Else it might work!

--HPS