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From: "Michael S. Tsirkin" <mst@redhat.com>
To: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Alex Chiang <achiang@hp.com>, Yu Zhao <yu.zhao@intel.com>,
	Matthew Wilcox <willy@linux.intel.com>,
	linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org,
	gleb@redhat.com
Subject: Re: [PATCH] pci: fix nit in ROM BAR size probing
Date: Wed, 4 Nov 2009 19:06:19 +0200	[thread overview]
Message-ID: <20091104170550.GA506@redhat.com> (raw)
In-Reply-To: <20091104090409.496540a1@jbarnes-piketon>

On Wed, Nov 04, 2009 at 09:04:09AM -0800, Jesse Barnes wrote:
> On Thu, 29 Oct 2009 17:24:59 +0200
> "Michael S. Tsirkin" <mst@redhat.com> wrote:
> 
> > When probing for ROM BAR size, we should not
> > change bits 1:10 in this BAR, because these
> > bits are marked as "reserved for future use" in PCI spec,
> > so changing them might have side effects.
> > 
> > No such issue for I/O or memory, as there is
> > an implementation note in PCI spec which explicitly allows
> > writing 0xfffffffff there.
> > 
> > Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> > ---
> >  drivers/pci/probe.c |    4 ++--
> >  1 files changed, 2 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
> > index 8105e32..d65aae4 100644
> > --- a/drivers/pci/probe.c
> > +++ b/drivers/pci/probe.c
> > @@ -163,12 +163,12 @@ int __pci_read_base(struct pci_dev *dev, enum
> > pci_bar_type type, {
> >  	u32 l, sz, mask;
> >  
> > -	mask = type ? ~PCI_ROM_ADDRESS_ENABLE : ~0;
> > +	mask = type ? PCI_ROM_ADDRESS_MASK : ~0;
> >  
> >  	res->name = pci_name(dev);
> >  
> >  	pci_read_config_dword(dev, pos, &l);
> > -	pci_write_config_dword(dev, pos, mask);
> > +	pci_write_config_dword(dev, pos, l | mask);
> >  	pci_read_config_dword(dev, pos, &sz);
> >  	pci_write_config_dword(dev, pos, l);
> 
> Applied to linux-next, thanks.  Another possible enhancement here would
> be to make the mask into a switch based on the type, since mem32 and
> mem64 "BARs" (added by willy for doing BAR-like stuff) could probably
> use ~0 as well.
> 
> Jesse

Where can I find the patch by willy that adds these?

-- 
MST

  reply	other threads:[~2009-11-04 17:08 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-10-29 15:24 [PATCH] pci: fix nit in ROM BAR size probing Michael S. Tsirkin
2009-11-04 17:04 ` Jesse Barnes
2009-11-04 17:06   ` Michael S. Tsirkin [this message]
2009-11-04 17:14     ` Jesse Barnes

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