[patch] ohci1394: don't leave interrupts enabled during suspend/resume

[Frans Pop <elendil@planet.nl>]

On my HP 2510p I get the following in dmesg during near the end of most
resumes from suspend to RAM:

irq 19: nobody cared (try booting with the "irqpoll" option)
Pid: 0, comm: swapper Not tainted 2.6.28-rc7 #67
Call Trace:
 <IRQ>  [<ffffffffa00ee9e1>] ? ohci_irq_handler+0x60/0x7e9 [ohci1394]
 [<ffffffff8026aa4d>] __report_bad_irq+0x38/0x87
 [<ffffffff8026abaa>] note_interrupt+0x10e/0x174
 [<ffffffff8026b262>] handle_fasteoi_irq+0xa7/0xd1
 [<ffffffff8020eb87>] do_IRQ+0x73/0xe4
 [<ffffffff8020c626>] ret_from_intr+0x0/0xa
 <EOI>  [<ffffffffa0012606>] ? acpi_idle_enter_bm+0x26b/0x2b2 [processor]
 [<ffffffffa00125fc>] ? acpi_idle_enter_bm+0x261/0x2b2 [processor]
 [<ffffffff8024f30f>] ? notifier_call_chain+0x33/0x5b
 [<ffffffff803b9c64>] ? cpuidle_idle_call+0x8c/0xc4
 [<ffffffff8020b312>] ? cpu_idle+0x4a/0x9a
 [<ffffffff8042c5c8>] ? rest_init+0x5c/0x5e
handlers:
[<ffffffffa00ee981>] (ohci_irq_handler+0x0/0x7e9 [ohci1394])
Disabling IRQ #19

There also seems to be an interrupt storm during suspend/resume when this
happens:
 19:      99968         33   IO-APIC-fasteoi   ohci1394

This patch gets rid of both issues and makes the resume as a whole
significantly faster.

Signed-off-by: Frans Pop <elendil@planet.nl>
Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>

---
New try and this actually _does_ seem to both make sense and work.

I've verified that the interrupt storm really only happens during the
suspend/resume process and not at other times.

I don't actually use firewire, so I cannot test anything other than
checking dmesg and seeing that there are no changes. With the patch
I do see a very slow increase of the interrupt count, so the device
seems active.

Please review the patch carefully, especially the error handling.
The patch is essentially only copy-and-paste work, with checks against
other drivers and the ohci1394_pci_probe function.

diff --git a/drivers/ieee1394/ohci1394.c b/drivers/ieee1394/ohci1394.c
index e509e13..d2942e6 100644
--- a/drivers/ieee1394/ohci1394.c
+++ b/drivers/ieee1394/ohci1394.c
@@ -3381,6 +3381,7 @@ static int ohci1394_pci_suspend(struct pci_dev *dev, pm_message_t state)
 	ohci_devctl(ohci->host, RESET_BUS, LONG_RESET_NO_FORCE_ROOT);
 	ohci_soft_reset(ohci);
 
+	free_irq(dev->irq, ohci);
 	err = pci_save_state(dev);
 	if (err) {
 		PRINT(KERN_ERR, "pci_save_state failed with %d", err);
@@ -3421,6 +3422,13 @@ static int ohci1394_pci_resume(struct pci_dev *dev)
 	reg_write(ohci, OHCI1394_IntEventClear, 0xffffffff);
 	reg_write(ohci, OHCI1394_IntMaskClear, 0xffffffff);
 	mdelay(50);
+
+	if (request_irq(dev->irq, ohci_irq_handler, IRQF_SHARED,
+			OHCI1394_DRIVER_NAME, ohci)) {
+		PRINT_G(KERN_ERR, "Failed to allocate interrupt %d", dev->irq);
+		return -EIO;
+        }
+
 	ohci_initialize(ohci);
 
 	hpsb_resume_host(ohci->host);