From 0f347aa07f15b346a001e557f4a0a45069f7fa3d Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Mon, 1 Feb 2021 17:34:19 +0100 Subject: [PATCH] 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: 71da201f38df ("ACPI: scan: Defer enumeration of devices with _DEP lists") Signed-off-by: Hans de Goede Signed-off-by: Rafael J. Wysocki --- drivers/acpi/scan.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index 1db063b02f63..22566b4b3150 100644 --- a/drivers/acpi/scan.c +++ b/drivers/acpi/scan.c @@ -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); -- 2.34.1