Fixing USB interrupt problems with ACPI enabled

From: Nakajima, Jun (jun.nakajima_at_intel.com)
Date: 08/30/03

  • Next message: Apurva Mehta: "Re: [PATCH]O19int" 
    Date:	Sat, 30 Aug 2003 08:47:41 -0700
To: "lkml" <linux-kernel@vger.kernel.org>, <acpi-devel@lists.sourceforge.net>

    Doing this for Len, who is on vacation. We would like to thank the
    people who provided debugging info such as acpidmp, dmidecode, and
    demsg. This is one of our findings, and we believe this would fix some
    interrupt problems (with USB, for example) with ACPI enabled, especially
    when the dmesg reads like:

    ACPI: PCI Interrupt Link [ALKA] enabled at IRQ 0
    ACPI: PCI Interrupt Link [ALKB] enabled at IRQ 0
    ACPI: PCI Interrupt Link [ALKC] enabled at IRQ 0
    ACPI: PCI Interrupt Link [ALKD] enabled at IRQ 0

    Basically we assumed that _CRS returned the one we set with _SRS, when
    setting up a PCI interrupt link device, but that's not the case with
    some AML codes. Some of them always return 0.
    Attached is a patch against 2.4.23-pre1. It should be easy to apply this
    to 2.6.

    Thanks,
    Jun
    ___
    diff -ru /build/orig/linux-2.4.23-pre1/drivers/acpi/pci_link.c
    linux-2.4.23-pre1/drivers/acpi/pci_link.c
    --- /build/orig/linux-2.4.23-pre1/drivers/acpi/pci_link.c
    2003-08-25 04:44:41.000000000 -0700
    +++ linux-2.4.23-pre1/drivers/acpi/pci_link.c 2003-08-29
    20:21:13.000000000 -0700
    @@ -216,7 +216,6 @@
             return AE_CTRL_TERMINATE;
     }
     
    -
     static int
     acpi_pci_link_get_current (
             struct acpi_pci_link *link)
    @@ -275,6 +274,26 @@
             return_VALUE(result);
     }
     
    +static int
    +acpi_pci_link_try_get_current (
    + struct acpi_pci_link *link,
    + int irq)
    +{
    + int result;
    +
    + result = acpi_pci_link_get_current(link);
    + if (result && link->irq.active) {
    + return_VALUE(result);
    + }
    +
    + if (!link->irq.active) {
    + ACPI_DEBUG_PRINT((ACPI_DB_ERROR, "No active IRQ resource
    found\n"));
    + printk(KERN_WARNING "_CRS returns NULL! Using IRQ %d for
    device (%s [%s]).\n", irq, acpi_device_name(link->device),
    acpi_device_bid(link->device));
    + link->irq.active = irq;
    + }
    +
    + return 0;
    +}
     
     static int
     acpi_pci_link_set (
    @@ -359,7 +378,7 @@
             }
     
             /* Make sure the active IRQ is the one we requested. */
    - result = acpi_pci_link_get_current(link);
    + result = acpi_pci_link_try_get_current(link, irq);
             if (result) {
                     return_VALUE(result);
             }
    @@ -573,10 +592,6 @@
                     else
                             printk(" %d", link->irq.possible[i]);
             }
    - if (!link->irq.active)
    - printk(", disabled");
    - else if (!found)
    - printk(", enabled at IRQ %d", link->irq.active);
             printk(")\n");
     
             /* TBD: Acquire/release lock */

    -
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