Hi Heiner,
On Sat, Feb 06, 2016 at 09:09:47AM +0100, Heiner Kallweit wrote:
> Am 06.02.2016 um 00:37 schrieb Rafael J. Wysocki:
> > On Saturday, February 06, 2016 12:00:32 AM Heiner Kallweit wrote:
> >> Since commit a44c386a361e "x86/PCI/ACPI: Recognize that Interrupt Line 255
> >> means "not connected"" I get several "PCI INT not connected" warnings on
> >> a Zotac CI321 and EHCI failes to load:
> >
> > That doesn't follow clearly from your report, but I'm assuming that it works
> > correctly without that commit, right?
> >
> Right, w/o this commit it looks like this:
>
> dmesg
> ehci-pci 0000:00:1d.0: irq 23, io mem 0xf7d1b000
>
> /proc/interrupts
> IO-APIC 23-fasteoi ehci_hcd:usb3
Thanks a lot for your report! This is a bit of a minefield, and I was
worried that we'd trip over something with a44c386a361e.
Oops, I think I see a problem with a44c386a361e. We're checking for
Interrupt Line == 255 even before we try to look it up in the _PRT. I
think we should only check Interrupt Line *after* everything else has
failed. Can you try the patch below instead of a44c386a361e?
If the patch below doesn't work, would you mind collecting the
complete output of "lspci -vvv" and the complete dmesg logs from
kernels with and without a44c386a361e, and putting them somewhere
(maybe a bugzilla.kernel.org report)?
Bjorn
diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
index d30184c..807a0a8 100644
--- a/drivers/acpi/pci_irq.c
+++ b/drivers/acpi/pci_irq.c
@@ -33,6 +33,7 @@
#include <linux/pci.h>
#include <linux/acpi.h>
#include <linux/slab.h>
+#include <linux/interrupt.h>
#define PREFIX "ACPI: "
@@ -387,6 +388,23 @@ static inline int acpi_isa_register_gsi(struct pci_dev *dev)
}
#endif
+static inline bool acpi_pci_irq_valid(struct pci_dev *dev, u8 pin)
+{
+#ifdef CONFIG_X86
+ /*
+ * On x86, Interrupt Line 0xff means "unknown" or "no connection"
+ * (PCI 3.0, Section 6.2.4, footnote on page 223).
+ */
+ if (dev->irq == 0xff) {
+ dev->irq = IRQ_NOTCONNECTED;
+ dev_warn(&dev->dev, "PCI INT %c: not connected\n",
+ pin_name(pin));
+ return false;
+ }
+#endif
+ return true;
+}
+
int acpi_pci_irq_enable(struct pci_dev *dev)
{
struct acpi_prt_entry *entry;
@@ -431,11 +449,14 @@ int acpi_pci_irq_enable(struct pci_dev *dev)
} else
gsi = -1;
- /*
- * No IRQ known to the ACPI subsystem - maybe the BIOS /
- * driver reported one, then use it. Exit in any case.
- */
if (gsi < 0) {
+ /*
+ * No IRQ known to the ACPI subsystem - maybe the BIOS /
+ * driver reported one, then use it. Exit in any case.
+ */
+ if (!acpi_pci_irq_valid(dev, pin))
+ return 0;
+
if (acpi_isa_register_gsi(dev))
dev_warn(&dev->dev, "PCI INT %c: no GSI\n",
pin_name(pin));
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 0e95fcc..358076e 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h
@@ -125,6 +125,16 @@ struct irqaction {
extern irqreturn_t no_action(int cpl, void *dev_id);
+/*
+ * If a (PCI) device interrupt is not connected we set dev->irq to
+ * IRQ_NOTCONNECTED. This causes request_irq() to fail with -ENOTCONN, so we
+ * can distingiush that case from other error returns.
+ *
+ * 0x80000000 is guaranteed to be outside the available range of interrupts
+ * and easy to distinguish from other possible incorrect values.
+ */
+#define IRQ_NOTCONNECTED (1U << 31)
+
extern int __must_check
request_threaded_irq(unsigned int irq, irq_handler_t handler,
irq_handler_t thread_fn,
diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 8411872..e79e60f 100644
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -1609,6 +1609,9 @@ int request_threaded_irq(unsigned int irq, irq_handler_t handler,
struct irq_desc *desc;
int retval;
+ if (irq == IRQ_NOTCONNECTED)
+ return -ENOTCONN;
+
/*
* Sanity-check: shared interrupts must pass in a real dev-ID,
* otherwise we'll have trouble later trying to figure out
@@ -1699,9 +1702,13 @@ EXPORT_SYMBOL(request_threaded_irq);
int request_any_context_irq(unsigned int irq, irq_handler_t handler,
unsigned long flags, const char *name, void *dev_id)
{
- struct irq_desc *desc = irq_to_desc(irq);
+ struct irq_desc *desc;
int ret;
+ if (irq == IRQ_NOTCONNECTED)
+ return -ENOTCONN;
+
+ desc = irq_to_desc(irq);
if (!desc)
return -EINVAL;
--
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