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authorArmin Wolf <W_Armin@gmx.de>2023-03-24 23:26:26 +0300
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2023-03-30 20:01:05 +0300
commit28f7b85895fce996c0f34827a7623ef6a031e4f3 (patch)
treeadecbc8627ce23b41fbcd37b556b19ae063f5a83 /drivers/acpi/ec.c
parent197b6b60ae7bc51dd0814953c562833143b292aa (diff)
downloadlinux-28f7b85895fce996c0f34827a7623ef6a031e4f3.tar.xz
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 <W_Armin@gmx.de> [ rjw: Comment adjustment ] Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/ec.c')
-rw-r--r--drivers/acpi/ec.c17
1 files changed, 14 insertions, 3 deletions
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);