Subject: [PATCH 1/2] [PCI] Check that MWI bit really did get set
Newsgroups: gmane.linux.network, gmane.linux.kernel
Date: 2006-10-06 19:05:18 GMT (2 years, 8 weeks, 1 day, 16 hours and 31 minutes ago)
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 <at> 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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