Date: Fri, 4 May 2012 21:41:55 +0200 From: Hans Petter Selasky <hselasky@c2i.net> To: Warner Losh <imp@bsdimp.com> Cc: "svn-src-stable@freebsd.org" <svn-src-stable@freebsd.org>, "svn-src-all@freebsd.org" <svn-src-all@freebsd.org>, "src-committers@freebsd.org" <src-committers@freebsd.org>, "svn-src-stable-9@freebsd.org" <svn-src-stable-9@freebsd.org>, John Baldwin <jhb@freebsd.org> Subject: Re: svn commit: r235007 - stable/9/sys/dev/pci Message-ID: <201205042141.55089.hselasky@c2i.net> In-Reply-To: <FEA446E9-A651-40F7-BFDD-1A2D41360EB8@bsdimp.com> References: <201205041538.q44FclqK010547@svn.freebsd.org> <201205041826.19435.hselasky@c2i.net> <FEA446E9-A651-40F7-BFDD-1A2D41360EB8@bsdimp.com>
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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
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