Yuji Shimada
2009-Apr-03 04:33 UTC
[Xen-devel] [PATCH] Don''t disable I/O decoding on reassigning resource
This patch does not disable I/O decoding on reassigning resource.
When I reserve UHCI for guest domain with "guestdev=" and
"reassign_resources" parameters, spurious interrupts occurred.
The reason is that UHCI is not reset by uhci_check_and_reset_hc
because I/O decoding is disabled. UHCI keeps asserting the interrupt
line. As a result spurious interrupts occur.
The patch does not disable I/O decoding. It disables only memory
decoding. So UHCI is reset and spurious interrupts do not occur.
Thanks,
--
Yuji Shimada
Signed-off-by: Yuji Shimada <shimada-yxb@necst.nec.co.jp>
diff -r 67a7ffcc5067 drivers/pci/quirks.c
--- a/drivers/pci/quirks.c Wed Apr 01 11:43:01 2009 +0100
+++ b/drivers/pci/quirks.c Fri Apr 03 13:10:53 2009 +0900
@@ -26,15 +26,16 @@
#ifdef CONFIG_PCI_REASSIGN
/*
- * This quirk function disables the device and releases resources
- * which is specified by kernel''s boot parameter
''reassigndev''.
+ * This quirk function disables memory decoding and releases memory
+ * resources which is specified by kernel''s boot parameter
''reassigndev''.
* Later on, kernel will assign page-aligned memory resource back
- * to that device.
+ * to the device.
*/
static void __devinit quirk_release_resources(struct pci_dev *dev)
{
int i;
struct resource *r;
+ u16 command;
if (pci_is_reassigndev(dev)) {
if (dev->hdr_type == PCI_HEADER_TYPE_NORMAL &&
@@ -43,9 +44,11 @@ static void __devinit quirk_release_reso
return;
}
printk(KERN_INFO
- "PCI: Disable device and release resources [%s].\n",
+ "PCI: Disable memory decoding and release memory resources
[%s].\n",
pci_name(dev));
- pci_disable_device(dev);
+ pci_read_config_word(dev, PCI_COMMAND, &command);
+ command &= ~PCI_COMMAND_MEMORY;
+ pci_write_config_word(dev, PCI_COMMAND, command);
for (i=0; i < PCI_NUM_RESOURCES; i++) {
r = &dev->resource[i];
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