linux-kernel - [PATCH] pci: fix nit in ROM BAR size probing

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Date:	Thu, 29 Oct 2009 17:24:59 +0200
From:	"Michael S. Tsirkin" <mst@...hat.com>
To:	Jesse Barnes <jbarnes@...tuousgeek.org>,
	Alex Chiang <achiang@...com>, Yu Zhao <yu.zhao@...el.com>,
	Matthew Wilcox <willy@...ux.intel.com>,
	linux-pci@...r.kernel.org, linux-kernel@...r.kernel.org,
	gleb@...hat.com
Subject: [PATCH] pci: fix nit in ROM BAR size probing

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@...hat.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);
 
-- 
1.6.5.rc2
--
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