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ACPI: EC: Limit explicit removal of query handlers to custom query handlers

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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>
This commit is contained in:
Armin Wolf 2023-03-24 21:26:26 +01:00 committed by Rafael J. Wysocki
parent 197b6b60ae
commit 28f7b85895
1 changed files with 14 additions and 3 deletions
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17
drivers/acpi/ec.c
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@ -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);