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ACPI: power: Skip duplicate power resource references in _PRx 

Some ACPI tables contain duplicate power resource references like this:

        Name (_PR0, Package (0x04)  // _PR0: Power Resources for D0
        {
            P28P,
            P18P,
            P18P,
            CLK4
        })

This causes a WARN_ON in sysfs_add_link_to_group() because we end up
adding a link to the same acpi_device twice:

sysfs: cannot create duplicate filename '/devices/LNXSYSTM:00/LNXSYBUS:00/PNP0A08:00/808622C1:00/OVTI2680:00/power_resources_D0/LNXPOWER:0a'
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.19.12-301.fc29.x86_64 #1
Hardware name: Insyde CherryTrail/Type2 - Board Product Name, BIOS jumperx.T87.KFBNEEA02 04/13/2016
Call Trace:
 dump_stack+0x5c/0x80
 sysfs_warn_dup.cold.3+0x17/0x2a
 sysfs_do_create_link_sd.isra.2+0xa9/0xb0
 sysfs_add_link_to_group+0x30/0x50
 acpi_power_expose_list+0x74/0xa0
 acpi_power_add_remove_device+0x50/0xa0
 acpi_add_single_object+0x26b/0x5f0
 acpi_bus_check_add+0xc4/0x250
 ...

To address this issue, make acpi_extract_power_resources() check for
duplicates and simply skip them when found.

Cc: All applicable <stable@vger.kernel.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
[ rjw: Subject & changelog, comments ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Hans de Goede 2018-12-30 18:25:00 +01:00 committed by Rafael J. Wysocki
parent 8fe28cb58b
commit 7d7b467cb9
1 changed files with 22 additions and 0 deletions
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22
drivers/acpi/power.c
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@ -131,6 +131,23 @@ void acpi_power_resources_list_free(struct list_head *list)
}
}
static bool acpi_power_resource_is_dup(union acpi_object *package,
unsigned int start, unsigned int i)
{
acpi_handle rhandle, dup;
unsigned int j;
/* The caller is expected to check the package element types */
rhandle = package->package.elements[i].reference.handle;
for (j = start; j < i; j++) {
dup = package->package.elements[j].reference.handle;
if (dup == rhandle)
return true;
}
return false;
}
int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
struct list_head *list)
{
@ -150,6 +167,11 @@ int acpi_extract_power_resources(union acpi_object *package, unsigned int start,
err = -ENODEV;
break;
}
/* Some ACPI tables contain duplicate power resource references */
if (acpi_power_resource_is_dup(package, start, i))
continue;
err = acpi_add_power_resource(rhandle);
if (err)
break;