[PATCH 1/2] [PCI] Check that MWI bit really did get set
[Posted October 17, 2006 by corbet]
| From: |
| Matthew Wilcox <matthew-AT-wil.cx> |
| To: |
| Val Henson <val_henson-AT-linux.intel.com>,
Greg Kroah-Hartman <gregkh-AT-suse.de> |
| Subject: |
| [PATCH 1/2] [PCI] Check that MWI bit really did get set |
| Date: |
| Fri, 06 Oct 2006 13:05:18 -0600 |
| Cc: |
| netdev-AT-vger.kernel.org, linux-pci-AT-atrey.karlin.mff.cuni.cz,
linux-kernel-AT-vger.kernel.org, Matthew Wilcox <matthew-AT-wil.cx> |
Since some devices may not implement the MWI bit, we should check that
the write did set it and return an error if it didn't.
Signed-off-by: Matthew Wilcox <matthew@wil.cx>
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index a544997..3d041f4 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -900,13 +900,17 @@ #endif
return rc;
pci_read_config_word(dev, PCI_COMMAND, &cmd);
- if (! (cmd & PCI_COMMAND_INVALIDATE)) {
- pr_debug("PCI: Enabling Mem-Wr-Inval for device %s\n", pci_name(dev));
- cmd |= PCI_COMMAND_INVALIDATE;
- pci_write_config_word(dev, PCI_COMMAND, cmd);
- }
-
- return 0;
+ if (cmd & PCI_COMMAND_INVALIDATE)
+ return 0;
+
+ pr_debug("PCI: Enabling Mem-Wr-Inval for device %s\n", pci_name(dev));
+ cmd |= PCI_COMMAND_INVALIDATE;
+ pci_write_config_word(dev, PCI_COMMAND, cmd);
+
+ /* read result from hardware (in case bit refused to enable) */
+ pci_read_config_word(dev, PCI_COMMAND, &cmd);
+
+ return (cmd & PCI_COMMAND_INVALIDATE) ? 0 : -EINVAL;
}
/**
-
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