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SubjectRe: [PATCH] pci: don't enable too much HT MSI mapping -v5 -resend
please try follwing patch over pci/linux-next

Thanks

YH

[PATCH] pci: don't enable too much HT MSI mapping -v6

Impact: fix bug

Prakash reported that his c51-mcp51 system ondie sound card doesn't work MSI
but if he hack out the HT-MSI on mcp51, the MSI will work well with sound card.

this patch rework the nv_msi_ht_cap_quirk()
and will only try to avoid to enable ht_msi on device following that root dev,
and don't touch that root dev

v6: only do that trick with end_device on the chain.

Reported-by: Prakash Punnoor <prakash@punnoor.de>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>

diff --git a/drivers/pci/quirks.c b/drivers/pci/quirks.c
index faf02dd..52714f2 100644
--- a/drivers/pci/quirks.c
+++ b/drivers/pci/quirks.c
@@ -2206,6 +2206,33 @@ static int __devinit host_bridge_with_leaf(struct pci_dev *host_bridge)
return found;
}

+#define PCI_HT_CAP_SLAVE_CTRL0 4 /* link control */
+#define PCI_HT_CAP_SLAVE_CTRL1 8 /* link control to */
+
+static int __devinit is_end_of_ht_chain(struct pci_dev *dev)
+{
+ int pos, ctrl_off;
+ int end = 0;
+ u16 flags, ctrl;
+
+ pos = pci_find_ht_capability(dev, HT_CAPTYPE_SLAVE);
+
+ if (!pos)
+ goto out;
+
+ pci_read_config_word(dev, pos + PCI_CAP_FLAGS, &flags);
+
+ ctrl_off = ((flags >> 10) & 1) ?
+ PCI_HT_CAP_SLAVE_CTRL0 : PCI_HT_CAP_SLAVE_CTRL1;
+ pci_read_config_word(dev, pos + ctrl_off, &ctrl);
+
+ if (ctrl & (1 << 6))
+ end = 1;
+
+out:
+ return end;
+}
+
static void __devinit nv_ht_enable_msi_mapping(struct pci_dev *dev)
{
struct pci_dev *host_bridge;
@@ -2230,8 +2257,9 @@ static void __devinit nv_ht_enable_msi_mapping(struct pci_dev *dev)
if (!found)
return;

- /* don't enable host_bridge with leaf directly here */
- if (host_bridge == dev && host_bridge_with_leaf(host_bridge))
+ /* don't enable end_device/host_bridge with leaf directly here */
+ if (host_bridge == dev && is_end_of_ht_chain(host_bridge) &&
+ host_bridge_with_leaf(host_bridge))
goto out;

/* root did that ! */

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