[PATCH 1/2] [PCI] Check that MWI bit really did get set

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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 <[email protected]>

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;
 }
 
 /**
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Index of Archives]     [Kernel Newbies]     [Netfilter]     [Bugtraq]     [Photo]     [Stuff]     [Gimp]     [Yosemite News]     [MIPS Linux]     [ARM Linux]     [Linux Security]     [Linux RAID]     [Video 4 Linux]     [Linux for the blind]     [Linux Resources]
  Powered by Linux