From 2e2eb55823df54b284acc365e0e5ad06d615d162 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Wed, 16 Mar 2022 13:37:44 +0100 Subject: [PATCH] Revert "ACPI: Pass the same capabilities to the _OSC regardless of the query flag" commit 2ca8e6285250c07a2e5a22ecbfd59b5a4ef73484 upstream. 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+VgQsVuQONVjKPpw0F5HKfiq=Gb6B5yw@mail.gmail.com Reported-by: Mario Limonciello Signed-off-by: Rafael J. Wysocki Tested-by: Mario Limonciello Acked-by: Huang Rui Reviewed-by: Mika Westerberg Signed-off-by: Greg Kroah-Hartman --- 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 dd535b4..3500744 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); } -- 2.7.4