Re: [PATCH] ACPI / power: Skip duplicate power-resources in PR tables

On Sun, Dec 30, 2018 at 6:25 PM Hans de Goede hdegoede@redhat.com wrote:

Some ACPI tables contain duplicate resources 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 ...

This commit makes acpi_extract_power_resources() check for duplicates and simply skips them when found, fixing this.

Cc: stable@vger.kernel.org Signed-off-by: Hans de Goede hdegoede@redhat.com

---

drivers/acpi/power.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+)

diff --git a/drivers/acpi/power.c b/drivers/acpi/power.c index 1b475bc1ae16..bc10a5efc1ba 100644 --- a/drivers/acpi/power.c +++ b/drivers/acpi/power.c @@ -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;
  

•   /* Note the element types have already been checked in our caller */
  

•   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 resources, skip these */
  

•           if (acpi_power_resource_is_dup(package, start, i))
  

•                   continue;
  

•           err = acpi_add_power_resource(rhandle);
            if (err)
                    break;
  

--

Applied, with some minor modifications in the subject, changelog and comments.

Thanks!