From 28f7b85895fce996c0f34827a7623ef6a031e4f3 Mon Sep 17 00:00:00 2001 From: Armin Wolf Date: Fri, 24 Mar 2023 21:26:26 +0100 Subject: ACPI: EC: Limit explicit removal of query handlers to custom query handlers According to the ACPI spec part 5.6.4.1.2, EC query handlers discovered thru ACPI should not be removed when a driver removes his custom query handler. On the Acer Travelmate 4002WLMi for example, such a query handler is used as a fallback to handle the EC SMBus alert when no driver is present. Change acpi_ec_remove_query_handlers() so that only custom query handlers are removed then remove_all is false. Query handlers discovered thru ACPI will still get removed when remove_all is true, which happens on device removal. Also add a simple check to ensure that acpi_ec_add_query_handler() is always called with either handle or func being set, since custom query handlers are detected based whether handlers->func is set or not. Tested on a Acer Travelmate 4002WLMi. Signed-off-by: Armin Wolf [ rjw: Comment adjustment ] Signed-off-by: Rafael J. Wysocki --- drivers/acpi/ec.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) (limited to 'drivers/acpi/ec.c') diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index 105d2e795afa..5ef72287d1be 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -1083,9 +1083,12 @@ int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit, acpi_handle handle, acpi_ec_query_func func, void *data) { - struct acpi_ec_query_handler *handler = - kzalloc(sizeof(struct acpi_ec_query_handler), GFP_KERNEL); + struct acpi_ec_query_handler *handler; + + if (!handle && !func) + return -EINVAL; + handler = kzalloc(sizeof(*handler), GFP_KERNEL); if (!handler) return -ENOMEM; @@ -1097,6 +1100,7 @@ int acpi_ec_add_query_handler(struct acpi_ec *ec, u8 query_bit, kref_init(&handler->kref); list_add(&handler->node, &ec->list); mutex_unlock(&ec->mutex); + return 0; } EXPORT_SYMBOL_GPL(acpi_ec_add_query_handler); @@ -1109,9 +1113,16 @@ static void acpi_ec_remove_query_handlers(struct acpi_ec *ec, mutex_lock(&ec->mutex); list_for_each_entry_safe(handler, tmp, &ec->list, node) { - if (remove_all || query_bit == handler->query_bit) { + /* + * When remove_all is false, only remove custom query handlers + * which have handler->func set. This is done to preserve query + * handlers discovered thru ACPI, as they should continue handling + * EC queries. + */ + if (remove_all || (handler->func && handler->query_bit == query_bit)) { list_del_init(&handler->node); list_add(&handler->node, &free_list); + } } mutex_unlock(&ec->mutex); -- cgit v1.2.3