linux-kernel - [PATCH 1/2] PCI: leave MEM and IO decoding disabled during 64-bit BAR sizing, too

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Message-ID: <20120709182018.18165.98339.stgit@bhelgaas.mtv.corp.google.com>
Date:	Mon, 09 Jul 2012 12:20:18 -0600
From:	Bjorn Helgaas <bhelgaas@...gle.com>
To:	linux-pci@...r.kernel.org
Cc:	Jacob Pan <jacob.jun.pan@...ux.intel.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org,
	Jesse Barnes <jbarnes@...tuousgeek.org>,
	Ivan Kokshaysky <ink@...assic.park.msu.ru>,
	Matthew Wilcox <matthew.r.wilcox@...el.com>,
	Robert Hancock <hancockrwd@...il.com>
Subject: [PATCH 1/2] PCI: leave MEM and IO decoding disabled during 64-bit BAR
	sizing, too

After 253d2e5498, we disable MEM and IO decoding for most devices while we
size 32-bit BARs.  However, we restore the original COMMAND register before
we size the upper 32 bits of 64-bit BARs, so we can still cause a conflict.

This patch waits to restore the original COMMAND register until we're
completely finished sizing the BAR.

Reference: https://lkml.org/lkml/2007/8/25/154
Signed-off-by: Bjorn Helgaas <bhelgaas@...gle.com>
---
 drivers/pci/probe.c |    6 +++---
 1 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 658ac97..66b3a6f 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -152,9 +152,6 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
 	pci_read_config_dword(dev, pos, &sz);
 	pci_write_config_dword(dev, pos, l);
 
-	if (!dev->mmio_always_on)
-		pci_write_config_word(dev, PCI_COMMAND, orig_cmd);
-
 	/*
 	 * All bits set in sz means the device isn't working properly.
 	 * If the BAR isn't implemented, all bits must be 0.  If it's a
@@ -239,6 +236,9 @@ int __pci_read_base(struct pci_dev *dev, enum pci_bar_type type,
 	}
 
  out:
+	if (!dev->mmio_always_on)
+		pci_write_config_word(dev, PCI_COMMAND, orig_cmd);
+
 	return (res->flags & IORESOURCE_MEM_64) ? 1 : 0;
  fail:
 	res->flags = 0;

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