This is a note to let you know that I've just added the patch titled ACPI: Pass the same capabilities to the _OSC regardless of the query flag to the 5.12-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: acpi-pass-the-same-capabilities-to-the-_osc-regardless-of-the-query-flag.patch and it can be found in the queue-5.12 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 159d8c274fd92438ca6d7068d7a5eeda157227f4 Mon Sep 17 00:00:00 2001 From: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> Date: Wed, 9 Jun 2021 13:25:33 +0300 Subject: ACPI: Pass the same capabilities to the _OSC regardless of the query flag From: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> commit 159d8c274fd92438ca6d7068d7a5eeda157227f4 upstream. Commit 719e1f561afb ("ACPI: Execute platform _OSC also with query bit clear") makes acpi_bus_osc_negotiate_platform_control() not only query the platforms capabilities but it also commits the result back to the firmware to report which capabilities are supported by the OS back to the firmware On certain systems the BIOS loads SSDT tables dynamically based on the capabilities the OS claims to support. However, on these systems the _OSC actually clears some of the bits (under certain conditions) so what happens is that now when we call the _OSC twice the second time we pass the cleared values and that results errors like below to appear on the system log: ACPI BIOS Error (bug): Could not resolve symbol [\_PR.PR00._CPC], AE_NOT_FOUND (20210105/psargs-330) ACPI Error: Aborting method \_PR.PR01._CPC due to previous error (AE_NOT_FOUND) (20210105/psparse-529) In addition the ACPI 6.4 spec says following [1]: If the OS declares support of a feature in the Support Field in one call to _OSC, then it must preserve the set state of that bit (declaring support for that feature) in all subsequent calls. Based on the above we can fix the issue by passing the same set of capabilities to the platform wide _OSC in both calls regardless of the query flag. While there drop the context.ret.length checks which were wrong to begin with (as the length is number of bytes not elements). This is already checked in acpi_run_osc() that also returns an error in that case. Includes fixes by Hans de Goede. [1] https://uefi.org/specs/ACPI/6.4/06_Device_Configuration/Device_Configuration.html#sequence-of-osc-calls BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=213023 BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1963717 Fixes: 719e1f561afb ("ACPI: Execute platform _OSC also with query bit clear") Cc: 5.12+ <stable@xxxxxxxxxxxxxxx> # 5.12+ Signed-off-by: Mika Westerberg <mika.westerberg@xxxxxxxxxxxxxxx> Reviewed-by: Hans de Goede <hdegoede@xxxxxxxxxx> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/acpi/bus.c | 27 ++++++++------------------- 1 file changed, 8 insertions(+), 19 deletions(-) --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -330,32 +330,21 @@ static void acpi_bus_osc_negotiate_platf if (ACPI_FAILURE(acpi_run_osc(handle, &context))) return; - capbuf_ret = context.ret.pointer; - if (context.ret.length <= OSC_SUPPORT_DWORD) { - kfree(context.ret.pointer); - return; - } + kfree(context.ret.pointer); - /* - * Now run _OSC again with query flag clear and with the caps - * supported by both the OS and the platform. - */ + /* Now run _OSC again with query flag clear */ 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; - 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; - } + 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); } Patches currently in stable-queue which might be from mika.westerberg@xxxxxxxxxxxxxxx are queue-5.12/acpi-pass-the-same-capabilities-to-the-_osc-regardless-of-the-query-flag.patch