Re: [PATCH v4 00/13] acpi: i2c: Use SharedAndWake and ExclusiveAndWake to enable wake irq

[Benjamin Tissoires <benjamin.tissoires@redhat.com>]

On Mon, Sep 19, 2022 at 5:59 PM Raul E Rangel <rrangel@chromium.org> wrote:
>
> Today, i2c drivers are making the assumption that their IRQs can also
> be used as wake IRQs. This isn't always the case and it can lead to
> spurious wakes. This has recently started to affect AMD Chromebooks.
> With the introduction of
> d62bd5ce12d7 ("pinctrl: amd: Implement irq_set_wake"), the AMD GPIO
> controller gained the capability to set the wake bit on each GPIO. The
> ACPI specification defines two ways to inform the system if a device is
> wake capable:
> 1) The _PRW object defines the GPE that can be used to wake the system.
> 2) Setting ExclusiveAndWake or SharedAndWake in the _CRS GpioInt.
>
> Currently only the first method is supported. The i2c drivers don't have
> any indication that the IRQ is wake capable, so they guess. This causes
> spurious interrupts, for example:
> * We have an ACPI HID device that has `_PR0` and `_PR3`. It doesn't have
>   `_PRW` or `ExclusiveAndWake` so that means the device can't wake the
>   system.
> * The IRQ line is active level low for this device and is pulled up by
>   the power resource defined in `_PR0`/`_PR3`.
> * The i2c driver will (incorrectly) arm the GPIO for wake by calling
>   `enable_irq_wake` as part of its suspend hook.
> * ACPI will power down the device since it doesn't have a wake GPE
>   associated with it.
> * When the device is powered down, the IRQ line will drop, and it will
>   trigger a wake event.
>
> See the following debug log:
> [   42.335804] PM: Suspending system (s2idle)
> [   42.340186] amd_gpio AMD0030:00: RX: Setting wake for pin 89 to enable
> [   42.467736]     power-0416 __acpi_power_off      : Power resource [PR00] turned off
> [   42.467739] device_pm-0280 device_set_power      : Device [H05D] transitioned to D3cold
> [   42.475210] PM: pm_system_irq_wakeup: 11 triggered pinctrl_amd
> [   42.535293] PM: Wakeup unrelated to ACPI SCI
> [   42.535294] PM: resume from suspend-to-idle
>
> In order to fix this, we need to take into account the wake capable bit
> defined on the Interrupt/GpioInt. This is accomplished by:
> * Migrating some of the i2c drivers over to using the PM subsystem to
>   manage the wake IRQ.
> * Expose the wake_capable bit from the ACPI Interrupt/GpioInt resource
>   to the  i2c core.
> * Use the wake_capable bit in the i2c core to call
>   `dev_pm_set_wake_irq`. This reuses the existing device tree flow.
> * Make the i2c drivers stop calling `dev_pm_set_wake_irq` since it's now
>   handled by the i2c core.
> * Make the ACPI device PM system aware of the wake_irq. This is
>   necessary so the device doesn't incorrectly get powered down when a
>   wake_irq is enabled.
>
> I've tested this code with various combinations of having _PRW,
> ExclusiveAndWake and power resources all defined or not defined, but it
> would be great if others could test this out on their hardware.
>
> I'm sure this will surface some devices where the IRQs were not
> correctly marked as wake capable. Ideally the firmware can be fixed, but
> if not we can work around this in the kernel by providing a board
> specific `struct i2c_board_info` with the `I2C_CLIENT_WAKE` flag set.
> See `chromeos_laptop.c` for an example of matching DMI properties and
> setting the `I2C_CLIENT_WAKE` override.
>
> Thanks,
> Raul
>
> Changes in v4:
> - Added Reviewed-by
> - Reformatted with 96 char limit
> - Removed unnecessary !!
> - Removed unrelated white space change
> - Renamed i2c_acpi_add_resource to i2c_acpi_add_irq_resource
> - Expanded logic in i2c_acpi_add_i2c_resource to make it easier to read
>
> Changes in v3:
> - Kept `acpi_dev_gpio_irq_get_by` unchanged to avoid having to touch
>   unrelated drivers.
> - Converted wake_capable parameter to bool.
> - Fixed bad indent
> - Convert wake_capable to bool
> - Only update wake_capable pointer once
> - Move wake_capable local into local block
>
> Changes in v2:
> - Added elants_i2c to series
> - Added raydium_ts_i2c to series
> - Fixed call site in mlxbf_gige_probe
> - Added ability to extract wake bit from Interrupt/IRQ resources
> - Look at wake_cabple bit for IRQ/Interrupt resources
> - I chose not to keep the legacy code around since systems without DT or ACPI should be rare.
>
> Raul E Rangel (13):
>   HID: i2c-hid: Use PM subsystem to manage wake irq
>   Input: elan_i2c - Use PM subsystem to manage wake irq
>   Input: elants_i2c - Use PM subsystem to manage wake irq
>   Input: raydium_ts_i2c - Use PM subsystem to manage wake irq
>   gpiolib: acpi: Add wake_capable variants of acpi_dev_gpio_irq_get
>   ACPI: resources: Add wake_capable parameter to acpi_dev_irq_flags
>   i2c: acpi: Use ACPI wake capability bit to set wake_irq
>   ACPI: PM: Take wake IRQ into consideration when entering
>     suspend-to-idle
>   HID: i2c-hid: acpi: Stop setting wakeup_capable
>   HID: i2c-hid: Don't set wake_capable and wake_irq
>   Input: elan_i2c - Don't set wake_capable and wake_irq
>   Input: elants_i2c - Don't set wake_capable and wake_irq
>   Input: raydium_ts_i2c - Don't set wake_capable and wake_irq
>
>  drivers/acpi/device_pm.c                   | 19 +++++++++--
>  drivers/acpi/irq.c                         |  8 +++--
>  drivers/acpi/resource.c                    | 23 ++++++++++----
>  drivers/gpio/gpiolib-acpi.c                | 15 +++++++--
>  drivers/gpio/gpiolib-acpi.h                |  2 ++
>  drivers/hid/i2c-hid/i2c-hid-acpi.c         |  5 ---
>  drivers/hid/i2c-hid/i2c-hid-core.c         | 24 ++------------
>  drivers/i2c/i2c-core-acpi.c                | 37 ++++++++++++++++------
>  drivers/i2c/i2c-core-base.c                |  6 +++-
>  drivers/i2c/i2c-core.h                     |  4 +--
>  drivers/input/mouse/elan_i2c_core.c        | 15 +--------
>  drivers/input/touchscreen/elants_i2c.c     | 13 ++------
>  drivers/input/touchscreen/raydium_i2c_ts.c |  7 +---
>  drivers/pnp/pnpacpi/rsparser.c             |  7 ++--
>  include/linux/acpi.h                       | 23 +++++++++++---
>  include/linux/ioport.h                     |  3 +-
>  16 files changed, 117 insertions(+), 94 deletions(-)
>

For the HID patches (1, 9, 10):
Acked-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

Feel free to take those through whatever tree is the best, we don't
have anything scheduled for i2c-hid for 6.1 right now.

Cheers,
Benjamin