Re: i2c designware change broke touchpad of a thinkpad

On 8/8/26 22:25, Andy Shevchenko wrote:
> On Sat, Aug 08, 2026 at 10:31:28PM +0530, Hardik Prakash wrote:
>> On Fri, 7 Aug 2026, Thorsten Leemhuis wrote:
>>> This became 0a4bb2abc3e56d ("i2c: designware: defer probe if child
>>> GpioInt controllers are not bound") and causes a regression for me: the
>>> Touchpad in my ThinkPad T14s Gen 4 (AMD) stopped working. From the
>>> kernel log:
>>>
>>> i2c_designware AMDI0010:01: i2c_dw_handle_tx_abort: lost arbitration
>>> i2c_designware AMDI0010:01: controller timed out
>>> i2c_hid_acpi i2c-SYNA8018:00: failed to fetch HID descriptor: -110
>>> i2c_hid_acpi i2c-SYNA8018:00: Failed to fetch the HID Descriptor
>>>
>>> Reverting this change in current mainline/master (f9a2394a23482) fixed
>>> things for me. Full dmesg of current master and master+revert can be
>>> found here:
>>>
>>> https://www.leemhuis.info/files/misc/dmesg-master
>>> https://www.leemhuis.info/files/misc/dmesg-master-plus_revert
>> [...]
>> Two things that would help narrow this down, whenever you have a moment:

Thx for looking into this. Here we go:

>> 1. A DSDT dump

https://www.leemhuis.info/files/misc/dsdt.dsl

>> 2. A dmesg with dynamic debug from a kernel built with the attached
>>    patch on top of current mainline/master

https://www.leemhuis.info/files/misc/dmesg-master-plus_revert

[    0.619018] i2c-dw-gpio-dbg: i2c_dw_check_gpio_dependencies(AMDI0010:00)
[    0.619018] i2c-dw-gpio-dbg: check_child_gpioint(adev=XXXX0000:00)
[    0.619076] i2c-dw-gpio-dbg: GpioInt resource_source=\_SB.GPIO (len=10)
[    0.619079] i2c-dw-gpio-dbg: acpi_fetch_acpi_dev() succeeded,
device=AMDI0030:00
[    0.619080] i2c-dw-gpio-dbg: gpio_device_find_by_fwnode() returned
NULL, deferring
[    0.619082] i2c-dw-gpio-dbg: check_child_gpioint ret=-517 (defer)
[    0.619102] i2c-dw-gpio-dbg: i2c_dw_check_gpio_dependencies(AMDI0010:01)
[    0.619104] i2c-dw-gpio-dbg: check_child_gpioint(adev=SYNA8018:00)
[    0.619159] i2c-dw-gpio-dbg: GpioInt resource_source=\_SB.GPIO (len=10)
[    0.619162] i2c-dw-gpio-dbg: acpi_fetch_acpi_dev() succeeded,
device=AMDI0030:00
[    0.619162] i2c-dw-gpio-dbg: gpio_device_find_by_fwnode() returned
NULL, deferring
[    0.619164] i2c-dw-gpio-dbg: check_child_gpioint ret=-517 (defer)
[    1.122517] i2c-dw-gpio-dbg: i2c_dw_check_gpio_dependencies(AMDI0010:00)
[    1.122523] i2c-dw-gpio-dbg: check_child_gpioint(adev=XXXX0000:00)
[    1.122625] i2c-dw-gpio-dbg: GpioInt resource_source=\_SB.GPIO (len=10)
[    1.122636] i2c-dw-gpio-dbg: acpi_fetch_acpi_dev() succeeded,
device=AMDI0030:00
[    1.122639] i2c-dw-gpio-dbg: gpio_device_find_by_fwnode() succeeded
[    1.122642] i2c-dw-gpio-dbg: device_is_bound()=true for AMDI0030:00
[    1.135894] i2c-dw-gpio-dbg: i2c_dw_check_gpio_dependencies(AMDI0010:01)
[    1.135898] i2c-dw-gpio-dbg: check_child_gpioint(adev=SYNA8018:00)
[    1.135976] i2c-dw-gpio-dbg: GpioInt resource_source=\_SB.GPIO (len=10)
[    1.135980] i2c-dw-gpio-dbg: acpi_fetch_acpi_dev() succeeded,
device=AMDI0030:00
[    1.135983] i2c-dw-gpio-dbg: gpio_device_find_by_fwnode() succeeded
[    1.135985] i2c-dw-gpio-dbg: device_is_bound()=true for AMDI0030:00
[    1.135987] i2c-dw-gpio-dbg: check_child_gpioint(adev=NXP1001:00)
[    1.136005] i2c-dw-gpio-dbg: GpioInt resource_source=\_SB.GPIO (len=10)
[    1.136008] i2c-dw-gpio-dbg: acpi_fetch_acpi_dev() succeeded,
device=AMDI0030:00
[    1.136009] i2c-dw-gpio-dbg: gpio_device_find_by_fwnode() succeeded
[    1.136010] i2c-dw-gpio-dbg: device_is_bound()=true for AMDI0030:00

HTH, Ciao, Thorsten

>> On Fri, 7 Aug 2026 at 19:37, Thorsten Leemhuis <[email protected]> wrote:
>>> On 7/28/26 10:30, Andi Shyti wrote:
>>>> On Sat, Jul 18, 2026 at 11:13:31AM +0530, Hardik Prakash wrote:
>>>>> I2C controllers may have child devices with GpioInt resources that
>>>>> depend on GPIO controllers being fully initialized. If the I2C
>>>>> controller probes and enumerates children before the referenced GPIO
>>>>> controller has completed probe, GPIO interrupts may not be properly
>>>>> configured, leading to device failures.
>>>>>
>>>>> On Lenovo Yoga 7 14AGP11, the WACF2200 touchscreen (child of
>>>>> AMDI0010:02) has a GpioInt resource pointing to GPIO 157 on the
>>>>> pinctrl-amd controller (AMDI0030:00). When i2c-designware probes
>>>>> AMDI0010:02 before pinctrl-amd finishes initializing, I2C transactions
>>>>> fail with lost arbitration errors:
>>>>>
>>>>>   0.285952  amd_gpio_probe: registering gpiochip  <- GPIO chip visible
>>>>>   0.287121  amd_gpio_probe: requesting parent IRQ <- probe still running
>>>>>   0.301454  AMDI0010:02 dw_i2c_plat_probe: start  <- races here
>>>>>   2.348157  lost arbitration
>>>>>
>>>>> Add a dependency check that walks ACPI child devices and defers probe
>>>>> until any referenced GPIO controller is bound.
> 
> [...]
> 
>>> #regzbot introduced: 0a4bb2abc3e56d
>>> #regzbot title i2c: designware: ThinkPad touchpad broke
>