From: "Rafael J. Wysocki" rafael.j.wysocki@intel.com
[ Upstream commit 2ca8e6285250c07a2e5a22ecbfd59b5a4ef73484 ]
Revert commit 159d8c274fd9 ("ACPI: Pass the same capabilities to the _OSC regardless of the query flag") which caused legitimate usage scenarios (when the platform firmware does not want the OS to control certain platform features controlled by the system bus scope _OSC) to break and was misguided by some misleading language in the _OSC definition in the ACPI specification (in particular, Section 6.2.11.1.3 "Sequence of _OSC Calls" that contradicts other perts of the _OSC definition).
Link: https://lore.kernel.org/linux-acpi/CAJZ5v0iStA0JmO0H3z+VgQsVuQONVjKPpw0F5HKf... Reported-by: Mario Limonciello Mario.Limonciello@amd.com Signed-off-by: Rafael J. Wysocki rafael.j.wysocki@intel.com Tested-by: Mario Limonciello mario.limonciello@amd.com Acked-by: Huang Rui ray.huang@amd.com Reviewed-by: Mika Westerberg mika.westerberg@linux.intel.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/acpi/bus.c | 27 +++++++++++++++++++-------- 1 file changed, 19 insertions(+), 8 deletions(-)
diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index dd535b4b9a16..3500744e6862 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -332,21 +332,32 @@ static void acpi_bus_osc_negotiate_platform_control(void) if (ACPI_FAILURE(acpi_run_osc(handle, &context))) return;
- kfree(context.ret.pointer); + capbuf_ret = context.ret.pointer; + if (context.ret.length <= OSC_SUPPORT_DWORD) { + kfree(context.ret.pointer); + return; + }
- /* Now run _OSC again with query flag clear */ + /* + * Now run _OSC again with query flag clear and with the caps + * supported by both the OS and the platform. + */ capbuf[OSC_QUERY_DWORD] = 0; + capbuf[OSC_SUPPORT_DWORD] = capbuf_ret[OSC_SUPPORT_DWORD]; + kfree(context.ret.pointer);
if (ACPI_FAILURE(acpi_run_osc(handle, &context))) return;
capbuf_ret = context.ret.pointer; - osc_sb_apei_support_acked = - capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_APEI_SUPPORT; - osc_pc_lpi_support_confirmed = - capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_PCLPI_SUPPORT; - osc_sb_native_usb4_support_confirmed = - capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_NATIVE_USB4_SUPPORT; + if (context.ret.length > OSC_SUPPORT_DWORD) { + osc_sb_apei_support_acked = + capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_APEI_SUPPORT; + osc_pc_lpi_support_confirmed = + capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_PCLPI_SUPPORT; + osc_sb_native_usb4_support_confirmed = + capbuf_ret[OSC_SUPPORT_DWORD] & OSC_SB_NATIVE_USB4_SUPPORT; + }
kfree(context.ret.pointer); }