Commits
Lv Zheng committed 307ecb0aa3a
ACPI / sysfs: Fix an issue for LoadTable opcode
OEM tables can be installed via RSDT/XSDT, in this case, they have already
been created under /sys/firmware/acpi/tables.
For this kind of tables, normally LoadTable opcode will be executed to load
them. If LoadTable opcode is executed after acpi_sysfs_init(),
acpi_sysfs_table_handler() will be invoked, thus a redundant table file
will be created under /sys/firmware/acpi/tables/dynamic. Then running
"acpidump" on such platform results in an error, complaining blank empty
table (see Link 1 below).
The bug can be reproduced by customizing an OEM1 table, allowing it to be
overridden via 'table_sigs' (drivers/acpi/tables.c), adding the following
code to the customized DSDT to load it:
Name (OEMH, Zero)
Name (OEMF, One)
If (LEqual (OEMF, One)) {
Store (LoadTable ("OEM1", "Intel", "Test"), OEMH)
Store (Zero, OEMF)
}
In order to make sure that the OEM1 table is installed after
acpi_sysfs_init(), acpi_sysfs_init() can be moved before invoking
acpi_load_tables(). Then the following command execution result can be
seen:
# acpidump > acpidump.txt
Could not read table header: /sysfs/firmware/acpi/tables/dynamic/OEM12
Could not get ACPI table at index 17, AE_BAD_HEADER
Link: https://bugzilla.kernel.org/show_bug.cgi?id=150841 # [1]
Link: https://github.com/acpica/acpica/commit/ed6a5fbc
Reported-by: Jason Voelz <jason.voelz@intel.com>
Reported-by: Francisco Leoner <francisco.j.lenoer.soto@intel.com>
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>