Re: AMD 8131 MSI quirk called too late, bus_flags not inherited ?

[Brice Goglin <brice@myri.com>]

On Mon, May 22, 2006 at 09:19:58PM -0700, Greg KH wrote:
> On Sun, May 21, 2006 at 03:24:07PM +0200, Brice Goglin wrote:
> > 
> > Right, thanks. Greg, what do you think of putting the attached patch in
> > 2.6.17 ?
> 
> Ok, does everyone agree that this patch fixes the issues for them?  I've
> had a few other private emails saying that the current code doesn't work
> properly and hadn't been able to determine what was happening.  Thanks
> for these patches.
> 
> > By the way, do we need to check dev->no_msi in pci_enable_msix() too ?
> 
> Yes, good catch, care to respin the patch and give it a good changelog
> entry?

Here you are:

The PCI_BUS_FLAGS_NO_MSI bus flags does not appear do be inherited
correctly from the amd8131 MSI quirk to its parent busses. It makes
devices behind a bridge behind amd8131 try to enable MSI while the
amd8131 does not support it.
We fix this by looking at flags of all parent busses in
pci_enable_msi() and pci_enable_msix().

By the way, also add the missing dev->no_msi check in pci_enable_msix()

Signed-off-by: Brice Goglin <brice@myri.com>

Index: linux-mm/drivers/pci/msi.c
===================================================================
--- linux-mm.orig/drivers/pci/msi.c	2006-05-21 15:12:04.000000000 +0200
+++ linux-mm/drivers/pci/msi.c	2006-05-23 08:31:02.000000000 +0200
@@ -916,6 +916,7 @@
  **/
 int pci_enable_msi(struct pci_dev* dev)
 {
+	struct pci_bus *bus;
 	int pos, temp, status = -EINVAL;
 	u16 control;
 
@@ -925,8 +926,9 @@
 	if (dev->no_msi)
 		return status;
 
-	if (dev->bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
-		return -EINVAL;
+	for (bus = dev->bus; bus; bus = bus->parent)
+		if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
+			return -EINVAL;
 
 	temp = dev->irq;
 
@@ -1162,6 +1164,7 @@
  **/
 int pci_enable_msix(struct pci_dev* dev, struct msix_entry *entries, int nvec)
 {
+	struct pci_bus *bus;
 	int status, pos, nr_entries, free_vectors;
 	int i, j, temp;
 	u16 control;
@@ -1170,6 +1173,13 @@
 	if (!pci_msi_enable || !dev || !entries)
  		return -EINVAL;
 
+	if (dev->no_msi)
+		return -EINVAL;
+
+	for (bus = dev->bus; bus; bus = bus->parent)
+		if (bus->bus_flags & PCI_BUS_FLAGS_NO_MSI)
+			return -EINVAL;
+
 	status = msi_init();
 	if (status < 0)
 		return status;