RE: [PATCH] ACPICA: Also handle "orphan" _REG methods for GPIO OpRegions

["Moore, Robert" <robert.moore@intel.com>]

Looks OK to me.
Bob


-----Original Message-----
From: Kaneda, Erik <erik.kaneda@intel.com> 
Sent: Monday, October 26, 2020 1:56 PM
To: Hans de Goede <hdegoede@redhat.com>; Rafael J . Wysocki <rjw@rjwysocki.net>; Len Brown <lenb@kernel.org>; Moore, Robert <robert.moore@intel.com>
Cc: linux-acpi@vger.kernel.org; devel@acpica.org
Subject: RE: [PATCH] ACPICA: Also handle "orphan" _REG methods for GPIO OpRegions



> -----Original Message-----
> From: Hans de Goede <hdegoede@redhat.com>
> Sent: Sunday, October 25, 2020 2:46 AM
> To: Rafael J . Wysocki <rjw@rjwysocki.net>; Len Brown 
> <lenb@kernel.org>; Moore, Robert <robert.moore@intel.com>; Kaneda, 
> Erik <erik.kaneda@intel.com>
> Cc: Hans de Goede <hdegoede@redhat.com>; linux-acpi@vger.kernel.org; 
> devel@acpica.org
> Subject: [PATCH] ACPICA: Also handle "orphan" _REG methods for GPIO 
> OpRegions
> 
> Before this commit acpi_ev_execute_reg_methods() had special handling 
> to handle "orphan" (no matching OpRegion declared) _REG methods for EC 
> nodes.
> 
> On Intel Cherry Trail devices there are 2 possible ACPI OpRegions for 
> accessing GPIOs. The standard GeneralPurposeIo OpRegion and the Cherry 
> Trail specific UserDefined 0x9X OpRegions.
> 
> Having 2 different types of OpRegions leads to potential issues with 
> checks for OpRegion availability, or in other words checks if _REG has 
> been called for the OpRegion which the ACPI code wants to use.
> 
> Except for the "orphan" EC handling, ACPICA core does not call _REG on 
> an ACPI node which does not define an OpRegion matching the type being 
> registered; and the reference design DSDT, from which most Cherry 
> Trail DSDTs are derived, does not define GeneralPurposeIo, nor
> UserDefined(0x93)
> OpRegions for the GPO2 (UID 3) device, because no pins were assigned 
> ACPI controlled functions in the reference design.
> 
> Together this leads to the perfect storm, at least on the Cherry Trail 
> based Medion Akayo E1239T. This design does use a GPO2 pin from its 
> ACPI code and has added the Cherry Trail specific UserDefined(0x93) 
> opregion to its GPO2 ACPI node to access this pin.
> 
> But it uses a has _REG been called availability check for the standard 
> GeneralPurposeIo OpRegion. This clearly is a bug in the DSDT, but this 
> does work under Windows. This issue leads to the intel_vbtn driver 
> reporting the device always being in tablet-mode at boot, even if it 
> is in laptop mode. Which in turn causes userspace to ignore touchpad 
> events. So iow this issues causes the touchpad to not work at boot.
> 
> This commit fixes this by extending the "orphan" _REG method handling 
> to also apply to GPIO address-space handlers.
> 
> Note it seems that Windows always calls "orphan" _REG methods so me 
> may want to consider dropping the space-id check and always do 
> "orphan" _REG method handling.
> 
> Signed-off-by: Hans de Goede <hdegoede@redhat.com>
> ---
>  drivers/acpi/acpica/evregion.c | 54 
> +++++++++++++++++-----------------
>  1 file changed, 27 insertions(+), 27 deletions(-)
> 
> diff --git a/drivers/acpi/acpica/evregion.c 
> b/drivers/acpi/acpica/evregion.c index 738d4b231f34..21ff341e34a4 
> 100644
> --- a/drivers/acpi/acpica/evregion.c
> +++ b/drivers/acpi/acpica/evregion.c
> @@ -21,7 +21,8 @@ extern u8 acpi_gbl_default_address_spaces[];
>  /* Local prototypes */
> 
>  static void
> -acpi_ev_orphan_ec_reg_method(struct acpi_namespace_node 
> *ec_device_node);
> +acpi_ev_execute_orphan_reg_method(struct acpi_namespace_node
> *device_node,
> +				  acpi_adr_space_type space_id);
> 
>  static acpi_status
>  acpi_ev_reg_run(acpi_handle obj_handle, @@ -684,10 +685,12 @@ 
> acpi_ev_execute_reg_methods(struct
> acpi_namespace_node *node,
>  				     ACPI_NS_WALK_UNLOCK,
> acpi_ev_reg_run, NULL,
>  				     &info, NULL);
> 
> -	/* Special case for EC: handle "orphan" _REG methods with no region
> */
> -
> -	if (space_id == ACPI_ADR_SPACE_EC) {
> -		acpi_ev_orphan_ec_reg_method(node);
> +	/*
> +	 * Special case for EC and GPIO: handle "orphan" _REG methods with
> +	 * no region.
> +	 */
> +	if (space_id == ACPI_ADR_SPACE_EC || space_id ==
> ACPI_ADR_SPACE_GPIO) {
> +		acpi_ev_execute_orphan_reg_method(node, space_id);
>  	}
> 
>  	ACPI_DEBUG_PRINT_RAW((ACPI_DB_NAMES,
> @@ -760,31 +763,28 @@ acpi_ev_reg_run(acpi_handle obj_handle,
> 
> 
> /**********************************************************
> *********************
>   *
> - * FUNCTION:    acpi_ev_orphan_ec_reg_method
> + * FUNCTION:    acpi_ev_execute_orphan_reg_method
>   *
> - * PARAMETERS:  ec_device_node      - Namespace node for an EC device
> + * PARAMETERS:  device_node     - Namespace node for an ACPI device
> + *              space_id        - The address space ID
>   *
>   * RETURN:      None
>   *
> - * DESCRIPTION: Execute an "orphan" _REG method that appears under 
> the EC
> + * DESCRIPTION: Execute an "orphan" _REG method that appears under an
> ACPI
>   *              device. This is a _REG method that has no corresponding region
> - *              within the EC device scope. The orphan _REG method appears to
> - *              have been enabled by the description of the ECDT in the ACPI
> - *              specification: "The availability of the region space can be
> - *              detected by providing a _REG method object underneath the
> - *              Embedded Controller device."
> - *
> - *              To quickly access the EC device, we use the ec_device_node used
> - *              during EC handler installation. Otherwise, we would need to
> - *              perform a time consuming namespace walk, executing _HID
> - *              methods to find the EC device.
> + *              within the device's scope. ACPI tables depending on these
> + *              "orphan" _REG methods have been seen for both EC and GPIO
> + *              Operation Regions. Presumably the Windows ACPI implementation
> + *              always calls the _REG method independent of the presence of
> + *              an actual Operation Region with the correct address space ID.
>   *
>   *  MUTEX:      Assumes the namespace is locked
>   *
> 
> **********************************************************
> ********************/
> 
>  static void
> -acpi_ev_orphan_ec_reg_method(struct acpi_namespace_node
> *ec_device_node)
> +acpi_ev_execute_orphan_reg_method(struct acpi_namespace_node
> *device_node,
> +				  acpi_adr_space_type space_id)
>  {
>  	acpi_handle reg_method;
>  	struct acpi_namespace_node *next_node; @@ -792,9 +792,9 @@ 
> acpi_ev_orphan_ec_reg_method(struct
> acpi_namespace_node *ec_device_node)
>  	struct acpi_object_list args;
>  	union acpi_object objects[2];
> 
> -	ACPI_FUNCTION_TRACE(ev_orphan_ec_reg_method);
> +	ACPI_FUNCTION_TRACE(ev_execute_orphan_reg_method);
> 
> -	if (!ec_device_node) {
> +	if (!device_node) {
>  		return_VOID;
>  	}
> 
> @@ -804,7 +804,7 @@ acpi_ev_orphan_ec_reg_method(struct
> acpi_namespace_node *ec_device_node)
> 
>  	/* Get a handle to a _REG method immediately under the EC device */
> 
> -	status = acpi_get_handle(ec_device_node, METHOD_NAME__REG,
> &reg_method);
> +	status = acpi_get_handle(device_node, METHOD_NAME__REG,
> &reg_method);
>  	if (ACPI_FAILURE(status)) {
>  		goto exit;	/* There is no _REG method present */
>  	}
> @@ -816,23 +816,23 @@ acpi_ev_orphan_ec_reg_method(struct
> acpi_namespace_node *ec_device_node)
>  	 * with other space IDs to be present; but the code below will then
>  	 * execute the _REG method with the embedded_control space_ID 
> argument.
>  	 */
> -	next_node = acpi_ns_get_next_node(ec_device_node, NULL);
> +	next_node = acpi_ns_get_next_node(device_node, NULL);
>  	while (next_node) {
>  		if ((next_node->type == ACPI_TYPE_REGION) &&
>  		    (next_node->object) &&
> -		    (next_node->object->region.space_id ==
> ACPI_ADR_SPACE_EC)) {
> +		    (next_node->object->region.space_id == space_id)) {
>  			goto exit;	/* Do not execute the _REG */
>  		}
> 
> -		next_node = acpi_ns_get_next_node(ec_device_node,
> next_node);
> +		next_node = acpi_ns_get_next_node(device_node,
> next_node);
>  	}
> 
> -	/* Evaluate the _REG(embedded_control,Connect) method */
> +	/* Evaluate the _REG(space_id, Connect) method */
> 
>  	args.count = 2;
>  	args.pointer = objects;
>  	objects[0].type = ACPI_TYPE_INTEGER;
> -	objects[0].integer.value = ACPI_ADR_SPACE_EC;
> +	objects[0].integer.value = space_id;
>  	objects[1].type = ACPI_TYPE_INTEGER;
>  	objects[1].integer.value = ACPI_REG_CONNECT;
> 
> --
> 2.28.0

This looks good to me. Bob, any thoughts?

Erik