linux-kernel - ohci1394: "irq 19: nobody cared" during resume from suspend to ram

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Date:	Sat, 6 Dec 2008 13:16:37 +0100
From:	Frans Pop <elendil@...net.nl>
To:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Cc:	linux1394-devel@...ts.sourceforge.net,
	Jarod Wilson <jwilson@...hat.com>,
	Stefan Richter <stefanr@...6.in-berlin.de>,
	"Rafael J. Wysocki" <rjw@...k.pl>
Subject: ohci1394: "irq 19: nobody cared" during resume from suspend to ram

After resume from suspend to RAM dmesg on my HP 2510p notebook shows:

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

Attached a dmesg that includes one suspend/resume cycle.
I only get the error once on resume, not at any other time.

While looking at the suspend and resume functions I noticed that the
suspend function calls free_irq before saving the PCI config, but there
is no corresponding request_irq in the resume function.

So I naively tried the following patch:

diff --git a/drivers/firewire/fw-ohci.c b/drivers/firewire/fw-ohci.c
index 46610b0..3f283df 100644
--- a/drivers/firewire/fw-ohci.c
+++ b/drivers/firewire/fw-ohci.c
@@ -2570,6 +2570,14 @@ static int pci_resume(struct pci_dev *dev)
 		fw_error("pci_enable_device failed\n");
 		return err;
 	}
+	if (request_irq(dev->irq, irq_handler,
+			IRQF_SHARED, ohci_driver_name, ohci)) {
+		fw_error("Failed to allocate shared interrupt %d.\n",
+			 dev->irq);
+		dma_free_coherent(ohci->card.device, CONFIG_ROM_SIZE,
+				  ohci->config_rom, ohci->config_rom_bus);
+		return -EIO;
+	}
 
 	return ohci_enable(&ohci->card, NULL, 0);
 }

And, hé presto, the error disappeared, and that's the only relevant diff
with a kernel without the patch.

Only after testing that did I notice that I had copied the call to
request_irq from ohci_enable, but that function is already getting called
immediately afterwards!

So it seems that the real problem is a timing issue and request_irq is
somehow being called too late during resume?

Could it be that the device is left in a half-active state (or that its
PCI config is saved while in a half-active state), resulting in IRQs
getting through before request_irq is executed in ohci_enable?

Note that I don't actually use firewire.

Note also that both with and without the error IRQ 19 is listed the same
in /proc/interrupts (and even with rather a high count for a device that
is not in use; this is shortly after a clean reboot + suspend/resume).

Cheers,
FJP

$ cat /proc/interrupts
           CPU0       CPU1
  0:      18744      10269   IO-APIC-edge      timer
  1:        115         41   IO-APIC-edge      i8042
  8:          1          0   IO-APIC-edge      rtc0
  9:        454        152   IO-APIC-fasteoi   acpi
 12:        342        139   IO-APIC-edge      i8042
 14:       4243       3517   IO-APIC-edge      ata_piix
 15:          0          0   IO-APIC-edge      ata_piix
 16:         46         11   IO-APIC-fasteoi   uhci_hcd:usb1, i915@pci:0000:00:02.0
 17:       1780       1583   IO-APIC-fasteoi   uhci_hcd:usb3, HDA Intel
 18:          2          2   IO-APIC-fasteoi   ehci_hcd:usb2, uhci_hcd:usb7, yenta
 19:      99968         33   IO-APIC-fasteoi   ohci1394
 20:         33         12   IO-APIC-fasteoi   ehci_hcd:usb4, uhci_hcd:usb5, mmc0
 22:          0          0   IO-APIC-fasteoi   uhci_hcd:usb6
508:       1335       1039   PCI-MSI-edge      iwlagn
NMI:          0          0   Non-maskable interrupts
LOC:      10382      14256   Local timer interrupts
RES:      10016       9596   Rescheduling interrupts
CAL:        173         36   Function call interrupts
TLB:         41         23   TLB shootdowns
TRM:          0          0   Thermal event interrupts
THR:          0          0   Threshold APIC interrupts
SPU:          0          0   Spurious interrupts
ERR:          1
MIS:          0

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