ACPI: resources: Add checks for ACPI IRQ override

The laptop keyboard doesn't work on many MEDION notebooks, but the
keyboard works well under Windows and Unix.

Through debugging, we found this log in the dmesg:

 ACPI: IRQ 1 override to edge, high
 pnp 00:03: Plug and Play ACPI device, IDs PNP0303 (active)

 And we checked the IRQ definition in the DSDT, it is:

    IRQ (Level, ActiveLow, Exclusive, )
        {1}

So the BIOS defines the keyboard IRQ to Level_Low, but the Linux
kernel override it to Edge_High. If the Linux kernel is modified
to skip the IRQ override, the keyboard will work normally.

From the existing comment in acpi_dev_get_irqresource(), the override
function only needs to be called when IRQ() or IRQNoFlags() is used
to populate the resource descriptor, and according to Section 6.4.2.1
of ACPI 6.4 [1], if IRQ() is empty or IRQNoFlags() is used, the IRQ
is High true, edge sensitive and non-shareable. ACPICA also assumes
that to be the case (see acpi_rs_set_irq[] in rsirq.c).

In accordance with the above, check 3 additional conditions
(EdgeSensitive, ActiveHigh and Exclusive) when deciding whether or
not to treat an ACPI_RESOURCE_TYPE_IRQ resource as "legacy", in which
case the IRQ override is applicable to it.

Link: https://uefi.org/specs/ACPI/6.4/06_Device_Configuration/Device_Configuration.html#irq-descriptor
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=213031
BugLink: http://bugs.launchpad.net/bugs/1909814
Suggested-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reported-by: Manuel Krause <manuelkrause@netscape.net>
Tested-by: Manuel Krause <manuelkrause@netscape.net>
Signed-off-by: Hui Wang <hui.wang@canonical.com>
[ rjw: Subject rewrite, changelog edits ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/acpi/resource.c b/drivers/acpi/resource.c
index ee78a210c6068645574b8a5954e14578efd7e564..dc01fb550b28dc6743b22594f859cee9f2ff4e33 100644 (file)
--- a/drivers/acpi/resource.c
+++ b/drivers/acpi/resource.c
@@ -423,6 +423,13 @@ static void acpi_dev_get_irqresource(struct resource *res, u32 gsi,
        }
 }
 
+static bool irq_is_legacy(struct acpi_resource_irq *irq)
+{
+       return irq->triggering == ACPI_EDGE_SENSITIVE &&
+               irq->polarity == ACPI_ACTIVE_HIGH &&
+               irq->shareable == ACPI_EXCLUSIVE;
+}
+
 /**
  * acpi_dev_resource_interrupt - Extract ACPI interrupt resource information.
  * @ares: Input ACPI resource object.
@@ -461,7 +468,7 @@ bool acpi_dev_resource_interrupt(struct acpi_resource *ares, int index,
                }
                acpi_dev_get_irqresource(res, irq->interrupts[index],
                                         irq->triggering, irq->polarity,
-                                        irq->shareable, true);
+                                        irq->shareable, irq_is_legacy(irq));
                break;
        case ACPI_RESOURCE_TYPE_EXTENDED_IRQ:
                ext_irq = &ares->data.extended_irq;