On Tue, Sep 20, 2022 at 4:43 AM Benjamin Tissoires
<benjamin.tissoires@xxxxxxxxxx> wrote:
>
> On Mon, Sep 19, 2022 at 5:59 PM Raul E Rangel <rrangel@xxxxxxxxxxxx> 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@xxxxxxxxxx>
>
> 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
>
Great thanks! I'll include your Acked-By in the next round.
