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Date: Sun, 16 Jun 2024 11:47:18 +0200
From: Hans de Goede <hdegoede@...hat.com>
To: "Rafael J. Wysocki" <rjw@...ysocki.net>,
Linux ACPI <linux-acpi@...r.kernel.org>
Cc: LKML <linux-kernel@...r.kernel.org>,
Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
VitaliiT <vitaly.torshyn@...il.com>, Armin Wolf <w_armin@....de>
Subject: Re: [PATCH v1] ACPI: EC: Evaluate orphan _REG under EC device
Hi,
On 6/12/24 4:15 PM, Rafael J. Wysocki wrote:
> From: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
>
> After starting to install the EC address space handler at the ACPI
> namespace root, if there is an "orphan" _REG method in the EC device's
> scope, it will not be evaluated any more. This breaks EC operation
> regions on some systems, like Asus gu605.
>
> To address this, use a wrapper around an existing ACPICA function to
> look for an "orphan" _REG method in the EC device scope and evaluate
> it if present.
>
> Fixes: 60fa6ae6e6d0 ("ACPI: EC: Install address space handler at the namespace root")
> Closes: https://bugzilla.kernel.org/show_bug.cgi?id=218945
> Reported-by: VitaliiT <vitaly.torshyn@...il.com>
> Tested-by: VitaliiT <vitaly.torshyn@...il.com>
> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
>
> Yes, this includes ACPICA changes that are obviously not upstream
> and I am going to take care of pusing them to upstream, but for
> now there is a regression to fix and it is relatively late in the
> cycle.
>
> ---
> drivers/acpi/acpica/acevents.h | 4 +++
> drivers/acpi/acpica/evregion.c | 6 ----
> drivers/acpi/acpica/evxfregn.c | 54 +++++++++++++++++++++++++++++++++++++++++
> drivers/acpi/ec.c | 3 ++
> include/acpi/acpixf.h | 4 +++
> 5 files changed, 66 insertions(+), 5 deletions(-)
>
> Index: linux-pm/drivers/acpi/acpica/evxfregn.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/acpica/evxfregn.c
> +++ linux-pm/drivers/acpi/acpica/evxfregn.c
> @@ -306,3 +306,57 @@ acpi_execute_reg_methods(acpi_handle dev
> }
>
> ACPI_EXPORT_SYMBOL(acpi_execute_reg_methods)
> +
> +/*******************************************************************************
> + *
> + * FUNCTION: acpi_execute_orphan_reg_method
> + *
> + * PARAMETERS: device - Handle for the device
> + * space_id - The address space ID
> + *
> + * RETURN: Status
> + *
> + * DESCRIPTION: Execute an "orphan" _REG method that appears under an ACPI
> + * device. This is a _REG method that has no corresponding region
> + * within the device's scope.
> + *
> + ******************************************************************************/
> +acpi_status
> +acpi_execute_orphan_reg_method(acpi_handle device, acpi_adr_space_type space_id)
> +{
> + struct acpi_namespace_node *node;
> + acpi_status status;
> +
> + ACPI_FUNCTION_TRACE(acpi_execute_orphan_reg_method);
> +
> + /* Parameter validation */
> +
> + if (!device) {
> + return_ACPI_STATUS(AE_BAD_PARAMETER);
> + }
> +
> + status = acpi_ut_acquire_mutex(ACPI_MTX_NAMESPACE);
> + if (ACPI_FAILURE(status)) {
> + return_ACPI_STATUS(status);
> + }
> +
> + /* Convert and validate the device handle */
> +
> + node = acpi_ns_validate_handle(device);
> + if (node) {
> +
> + /*
> + * If an "orphan" _REG method is present in the device's scope
> + * for the given address space ID, run it.
> + */
> +
> + acpi_ev_execute_orphan_reg_method(node, space_id);
> + } else {
> + status = AE_BAD_PARAMETER;
> + }
> +
> + (void)acpi_ut_release_mutex(ACPI_MTX_NAMESPACE);
> + return_ACPI_STATUS(status);
> +}
> +
> +ACPI_EXPORT_SYMBOL(acpi_execute_orphan_reg_method)
> Index: linux-pm/include/acpi/acpixf.h
> ===================================================================
> --- linux-pm.orig/include/acpi/acpixf.h
> +++ linux-pm/include/acpi/acpixf.h
> @@ -663,6 +663,10 @@ ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> acpi_adr_space_type
> space_id))
> ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> + acpi_execute_orphan_reg_method(acpi_handle device,
> + acpi_adr_space_type
> + space_id))
> +ACPI_EXTERNAL_RETURN_STATUS(acpi_status
> acpi_remove_address_space_handler(acpi_handle
> device,
> acpi_adr_space_type
> Index: linux-pm/drivers/acpi/acpica/acevents.h
> ===================================================================
> --- linux-pm.orig/drivers/acpi/acpica/acevents.h
> +++ linux-pm/drivers/acpi/acpica/acevents.h
> @@ -191,6 +191,10 @@ void
> acpi_ev_execute_reg_methods(struct acpi_namespace_node *node,
> acpi_adr_space_type space_id, u32 function);
>
> +void
> +acpi_ev_execute_orphan_reg_method(struct acpi_namespace_node *node,
> + acpi_adr_space_type space_id);
> +
> acpi_status
> acpi_ev_execute_reg_method(union acpi_operand_object *region_obj, u32 function);
>
> Index: linux-pm/drivers/acpi/acpica/evregion.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/acpica/evregion.c
> +++ linux-pm/drivers/acpi/acpica/evregion.c
> @@ -20,10 +20,6 @@ extern u8 acpi_gbl_default_address_space
>
> /* Local prototypes */
>
> -static void
> -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,
> u32 level, void *context, void **return_value);
> @@ -818,7 +814,7 @@ acpi_ev_reg_run(acpi_handle obj_handle,
> *
> ******************************************************************************/
>
> -static void
> +void
> acpi_ev_execute_orphan_reg_method(struct acpi_namespace_node *device_node,
> acpi_adr_space_type space_id)
> {
> Index: linux-pm/drivers/acpi/ec.c
> ===================================================================
> --- linux-pm.orig/drivers/acpi/ec.c
> +++ linux-pm/drivers/acpi/ec.c
> @@ -1507,6 +1507,9 @@ static int ec_install_handlers(struct ac
>
> if (call_reg && !test_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags)) {
> acpi_execute_reg_methods(scope_handle, ACPI_ADR_SPACE_EC);
> + if (scope_handle != ec->handle)
> + acpi_execute_orphan_reg_method(ec->handle, ACPI_ADR_SPACE_EC);
> +
> set_bit(EC_FLAGS_EC_REG_CALLED, &ec->flags);
> }
>
TL;DR: this change made me wonder about a possible issue, but all is
fine, except that the code flow leading to "fine" is a bit convoluted.
I noticed this landing in Linus' tree and this got me thinking about
if the "if (scope_handle != ec->handle)" would not cause the orphan
_REG method to not get called for the case where the EC is created
by parsing the ECDT early on, since then we set
ec->handle = ACPI_ROOT_OBJECT for the ec object.
So I checked and acpi_ec_ecdt_probe() calls acpi_ec_setup(ec, NULL, false)
with the false making call_reg above false, so the _REG methods do not
get executed at this point.
Instead they should get executed when parsing the DSDT finds the EC ACPI
device by acpi_ec_add() calling acpi_ec_setup(ec, device, true).
acpi_ec_add() updated ec->handle away from ACPI_ROOT_OBJECT to the actual
acpi_device's handle before calling acpi_ec_setup(ec, device, true) so
all should be well.
But while checkimg this I noticed a pre-existing issue where if the boot_ec
object is created from the ECDT, so with ec->handle == NULL, acpi_ec_add()
does not update ec->handle, which means an orphan _REG method will not get
executed.
Specifically if this if condition evaluated to true, because the !strcmp()
evaluates to true:
if (boot_ec && (boot_ec->handle == device->handle ||
!strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
/* Fast path: this device corresponds to the boot EC. */
ec = boot_ec;
} else {
then [boot_]ec->handle does not get set to device->handle .
So at a first glance it looks like we need something like this to make sure
that any orphan _REG methods are also run in the described scenario:
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
index e7793ee9e649..af61b9bb3749 100644
--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -1635,6 +1635,7 @@ static int acpi_ec_add(struct acpi_device *device)
!strcmp(acpi_device_hid(device), ACPI_ECDT_HID))) {
/* Fast path: this device corresponds to the boot EC. */
ec = boot_ec;
+ ec->handle = device->handle;
} else {
acpi_status status;
But upon further checking the only place creating an acpi_device
with an ACPI_ECDT_HID is acpi_ec_ecdt_start() which does:
status = acpi_get_handle(NULL, ecdt_ptr->id, &handle);
if (ACPI_SUCCESS(status)) {
boot_ec->handle = handle;
/* Add a special ACPI device object to represent the boot EC. */
acpi_bus_register_early_device(ACPI_BUS_TYPE_ECDT_EC);
}
So boot_ec->handle gets updated in this case before acpi_ec_add() runs
and everything is fine.
...
Still I'm wondering if it would not be better to replace this
"boot_ec->handle = handle;" in acpi_ec_ecdt_start() with the change
from my proposed diff above, so that we consistently about the
[boot_]ec->handle with device->handle for the being added acpi_device
in both branches of the if ... else ... in acpi_ec_add() ?
Regards,
Hans
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