From 80e228a4e832f200e1f8206711ce70cc10c57e12 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" Revert commit 9227c3a1782b ("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 --- 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 647791d34c19f..c7670d441ad9e 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); } -- 2.39.5