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ACPI: scan: Fix battery devices sometimes never binding 

With the new 2 step scanning process, which defers instantiating some
ACPI-devices based on their _DEP to the second step, the following may
happen:

1. During the first acpi_walk_namespace(acpi_bus_check_add) call
   acpi_scan_check_dep() gets called on the Battery ACPI dev handle and
   adds one or more deps for this handle to the acpi_dep_list

2. During the first acpi_bus_attach() call one or more of the suppliers of
   these deps get their driver attached and
   acpi_walk_dep_device_list(supplier_handle) gets called.

   At this point acpi_bus_get_device(dep->consumer) get called,
   but since the battery has DEPs it has not been instantiated during the
   first acpi_walk_namespace(acpi_bus_check_add), so the
   acpi_bus_get_device(dep->consumer) call fails.

   Before this commit, acpi_walk_dep_device_list() would now continue
   *without* removing the acpi_dep_data entry for this supplier,consumer
   pair from the acpi_dep_list.

3. During the second acpi_walk_namespace(acpi_bus_check_add) call
   an acpi_device gets instantiated for the battery and
   acpi_scan_dep_init() gets called to initialize its dep_unmet val.

   Before this commit, the dep_unmet count would include DEPs for
   suppliers for which acpi_walk_dep_device_list(supplier_handle)
   has already been called, so it will never become 0 and the
   ACPI battery driver will never get attached / bind.

Fix the ACPI battery driver never binding in this scenario by making
acpi_walk_dep_device_list() always remove matching acpi_dep_data
entries independent of the acpi_bus_get_device(dep->consumer) call
succeeding or not.

Fixes: 71da201f38 ("ACPI: scan: Defer enumeration of devices with _DEP lists")
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This commit is contained in:
Hans de Goede 2021-02-01 17:34:19 +01:00 committed by Rafael J. Wysocki
parent 1048ba83fb
commit 0f347aa07f
1 changed files with 5 additions and 5 deletions
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10
drivers/acpi/scan.c
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@ -2123,12 +2123,12 @@ void acpi_walk_dep_device_list(acpi_handle handle)
list_for_each_entry_safe(dep, tmp, &acpi_dep_list, node) {
if (dep->supplier == handle) {
acpi_bus_get_device(dep->consumer, &adev);
if (!adev)
continue;
adev->dep_unmet--;
if (!adev->dep_unmet)
acpi_bus_attach(adev, true);
if (adev) {
adev->dep_unmet--;
if (!adev->dep_unmet)
acpi_bus_attach(adev, true);
}
list_del(&dep->node);
kfree(dep);