commit b1c0330823fe upstream.

Backport of ACPI fix for #199981 for linux-4.9.y, tested on an Asus EeePC 1005PE running Debian Buster.

Some systems have had functional issues since commit 5a8361f7ecce (ACPICA: Integrate package handling with module-level code) that, among other things, changed the initial values of the acpi_gbl_group_module_level_code and acpi_gbl_parse_table_as_term_list global flags in ACPICA which implicitly caused acpi_ec_ecdt_probe() to be called before acpi_load_tables() on the vast majority of platforms.

Namely, before commit 5a8361f7ecce, acpi_load_tables() was called from acpi_early_init() if acpi_gbl_parse_table_as_term_list was FALSE and acpi_gbl_group_module_level_code was TRUE, which almost always was the case as FALSE and TRUE were their initial values, respectively. The acpi_gbl_parse_table_as_term_list value would be changed to TRUE for a couple of platforms in acpi_quirks_dmi_table[], but it remained FALSE in the vast majority of cases.

After commit 5a8361f7ecce, the initial values of the two flags have been reversed, so in effect acpi_load_tables() has not been called from acpi_early_init() any more. That, in turn, affects acpi_ec_ecdt_probe() which is invoked before acpi_load_tables() now and it is not possible to evaluate the _REG method for the EC address space handler installed by it. That effectively causes the EC address space to be inaccessible to AML on platforms with an ECDT matching the EC device definition in the DSDT and functional problems ensue in there.

Because the default behavior before commit 5a8361f7ecce was to call acpi_ec_ecdt_probe() after acpi_load_tables(), it should be safe to do that again. Moreover, the EC address space handler installed by acpi_ec_ecdt_probe() is only needed for AML to be able to access the EC address space and the only AML that can run during acpi_load_tables() is module-level code which only is allowed to access address spaces with default handlers (memory, I/O and PCI config space).

For this reason, move the acpi_ec_ecdt_probe() invocation back to acpi_bus_init(), from where it was taken away by commit d737f333b211 (ACPI: probe ECDT before loading AML tables regardless of module-level code flag), and put it after the invocation of acpi_load_tables() to restore the original code ordering from before commit 5a8361f7ecce.

Fixes: 5a8361f7ecce ("ACPICA: Integrate package handling with module-level code") Link: https://bugzilla.kernel.org/show_bug.cgi?id=199981 Reported-by: step-ali sunmooon15@gmail.com Reported-by: Charles Stanhope charles.stanhope@gmail.com Tested-by: Charles Stanhope charles.stanhope@gmail.com Reported-by: Paulo Nascimento paulo.ulusu@googlemail.com Reported-by: David Purton dcpurton@marshwiggle.net Reported-by: Adam Harvey adam@adamharvey.name Reported-by: Zhang Rui rui.zhang@intel.com Tested-by: Zhang Rui rui.zhang@intel.com Tested-by: Jean-Marc Lenoir archlinux@jihemel.com Tested-by: Laurentiu Pancescu laurentiu@laurentiupancescu.com Signed-off-by: Laurentiu Pancescu laurentiu@laurentiupancescu.com --- drivers/acpi/bus.c | 23 ++++++++++++----------- 1 file changed, 12 insertions(+), 11 deletions(-)

diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index 92a146861086..cc88571c2cac 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -1133,17 +1133,6 @@ static int __init acpi_bus_init(void)

acpi_os_initialize1();

- /* - * ACPI 2.0 requires the EC driver to be loaded and work before - * the EC device is found in the namespace (i.e. before - * acpi_load_tables() is called). - * - * This is accomplished by looking for the ECDT table, and getting - * the EC parameters out of that. - */ - status = acpi_ec_ecdt_probe(); - /* Ignore result. Not having an ECDT is not fatal. */ - if (acpi_gbl_execute_tables_as_methods || !acpi_gbl_group_module_level_code) { status = acpi_load_tables(); @@ -1154,6 +1143,18 @@ static int __init acpi_bus_init(void) } }

+ /* + * ACPI 2.0 requires the EC driver to be loaded and work before the EC + * device is found in the namespace. + * + * This is accomplished by looking for the ECDT table and getting the EC + * parameters out of that. + * + * Do that before calling acpi_initialize_objects() which may trigger EC + * address space accesses. + */ + acpi_ec_ecdt_probe(); + status = acpi_enable_subsystem(ACPI_NO_ACPI_ENABLE); if (ACPI_FAILURE(status)) { printk(KERN_ERR PREFIX