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

Warner Losh imp at
Fri May 4 17:23:24 UTC 2012

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:
>>> 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...


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