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Subject[patch 069/114] PCI: dont enable too many HT MSI mappings
2.6.28-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Yinghai Lu <yinghai@kernel.org>

commit 1dec6b054dd1fc780e18b815068bf5677409eb2d upstream.

Prakash reported that his c51-mcp51 ondie sound card doesn't work with
MSI. But if he hacks out the HT-MSI quirk, MSI works fine.

So this patch reworks the nv_msi_ht_cap_quirk(). It will now only
enable ht_msi on own its root device, avoiding enabling it on devices
following that root dev.

Reported-by: Prakash Punnoor <prakash@punnoor.de>
Tested-by: Prakash Punnoor <prakash@punnoor.de>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Jesse Barnes <jbarnes@hobbes.lan>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/pci/quirks.c | 115 ++++++++++++++++++++++++++++++++++++++++++++-------
1 file changed, 100 insertions(+), 15 deletions(-)
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -1847,10 +1847,100 @@ DECLARE_PCI_FIXUP_EARLY(PCI_VENDOR_ID_NV
PCI_DEVICE_ID_NVIDIA_NVENET_15,
nvenet_msi_disable);

-static void __devinit nv_msi_ht_cap_quirk(struct pci_dev *dev)
+static void __devinit nv_ht_enable_msi_mapping(struct pci_dev *dev)
{
struct pci_dev *host_bridge;
+ int pos;
+ int i, dev_no;
+ int found = 0;
+
+ dev_no = dev->devfn >> 3;
+ for (i = dev_no; i >= 0; i--) {
+ host_bridge = pci_get_slot(dev->bus, PCI_DEVFN(i, 0));
+ if (!host_bridge)
+ continue;
+
+ pos = pci_find_ht_capability(host_bridge, HT_CAPTYPE_SLAVE);
+ if (pos != 0) {
+ found = 1;
+ break;
+ }
+ pci_dev_put(host_bridge);
+ }
+
+ if (!found)
+ return;
+
+ /* root did that ! */
+ if (msi_ht_cap_enabled(host_bridge))
+ goto out;
+
+ ht_enable_msi_mapping(dev);
+
+out:
+ pci_dev_put(host_bridge);
+}
+
+static void __devinit ht_disable_msi_mapping(struct pci_dev *dev)
+{
+ int pos, ttl = 48;
+
+ pos = pci_find_ht_capability(dev, HT_CAPTYPE_MSI_MAPPING);
+ while (pos && ttl--) {
+ u8 flags;
+
+ if (pci_read_config_byte(dev, pos + HT_MSI_FLAGS,
+ &flags) == 0) {
+ dev_info(&dev->dev, "Enabling HT MSI Mapping\n");
+
+ pci_write_config_byte(dev, pos + HT_MSI_FLAGS,
+ flags & ~HT_MSI_FLAGS_ENABLE);
+ }
+ pos = pci_find_next_ht_capability(dev, pos,
+ HT_CAPTYPE_MSI_MAPPING);
+ }
+}
+
+static int __devinit ht_check_msi_mapping(struct pci_dev *dev)
+{
int pos, ttl = 48;
+ int found = 0;
+
+ /* check if there is HT MSI cap or enabled on this device */
+ pos = pci_find_ht_capability(dev, HT_CAPTYPE_MSI_MAPPING);
+ while (pos && ttl--) {
+ u8 flags;
+
+ if (found < 1)
+ found = 1;
+ if (pci_read_config_byte(dev, pos + HT_MSI_FLAGS,
+ &flags) == 0) {
+ if (flags & HT_MSI_FLAGS_ENABLE) {
+ if (found < 2) {
+ found = 2;
+ break;
+ }
+ }
+ }
+ pos = pci_find_next_ht_capability(dev, pos,
+ HT_CAPTYPE_MSI_MAPPING);
+ }
+
+ return found;
+}
+
+static void __devinit nv_msi_ht_cap_quirk(struct pci_dev *dev)
+{
+ struct pci_dev *host_bridge;
+ int pos;
+ int found;
+
+ /* check if there is HT MSI cap or enabled on this device */
+ found = ht_check_msi_mapping(dev);
+
+ /* no HT MSI CAP */
+ if (found == 0)
+ return;

/*
* HT MSI mapping should be disabled on devices that are below
@@ -1866,24 +1956,19 @@ static void __devinit nv_msi_ht_cap_quir
pos = pci_find_ht_capability(host_bridge, HT_CAPTYPE_SLAVE);
if (pos != 0) {
/* Host bridge is to HT */
- ht_enable_msi_mapping(dev);
+ if (found == 1) {
+ /* it is not enabled, try to enable it */
+ nv_ht_enable_msi_mapping(dev);
+ }
return;
}

- /* Host bridge is not to HT, disable HT MSI mapping on this device */
- pos = pci_find_ht_capability(dev, HT_CAPTYPE_MSI_MAPPING);
- while (pos && ttl--) {
- u8 flags;
+ /* HT MSI is not enabled */
+ if (found == 1)
+ return;

- if (pci_read_config_byte(dev, pos + HT_MSI_FLAGS,
- &flags) == 0) {
- dev_info(&dev->dev, "Disabling HT MSI mapping");
- pci_write_config_byte(dev, pos + HT_MSI_FLAGS,
- flags & ~HT_MSI_FLAGS_ENABLE);
- }
- pos = pci_find_next_ht_capability(dev, pos,
- HT_CAPTYPE_MSI_MAPPING);
- }
+ /* Host bridge is not to HT, disable HT MSI mapping on this device */
+ ht_disable_msi_mapping(dev);
}
DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID, nv_msi_ht_cap_quirk);
DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_AL, PCI_ANY_ID, nv_msi_ht_cap_quirk);



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