Re: [PATCH] Revert "i2c: designware: defer probe if child GpioInt controllers are not bound"
Andi Shyti <[email protected]>
| Newsgroups | org.kernel.vger.linux-i2c,org.kernel.vger.linux-gpio,org.kernel.vger.linux-kernel |
|---|---|
| Message-ID | <[email protected]> |
Hi Hardik, On Fri, Aug 14, 2026 at 03:37:19PM +0530, Hardik Prakash wrote: > This reverts commit 0a4bb2abc3e56d7be6e69b050c88ba52c87e22bf. > > The reverted commit causes a regression on ThinkPad T14s Gen 4 (AMD): > the touchpad's I2C controller fails with lost arbitration errors, > because it delays i2c-designware's probe by roughly 500ms, which > shifts the touchpad's first HID descriptor fetch into a window where > the platform's embedded controller is still acting as a secondary I2C > bus master. Debug tracing confirms the GpioInt dependency check itself > behaves correctly (it defers appropriately and confirms the GPIO > controller is bound); the arbitration failure happens roughly a > second after the check passes, when i2c_hid_acpi's own probe attempts > its first transaction. > > The original fix is still needed for the Lenovo Yoga 7 14AGP11 > touchscreen race the commit addressed, but a corrected version will > be resubmitted once the EC bus-mastering interaction is understood > and handled properly, rather than reintroducing a different > regression on more widely-used ThinkPad hardware in the meantime. > > Reported-by: Thorsten Leemhuis <[email protected]> > Closes: https://lore.kernel.org/all/[email protected]/ > Signed-off-by: Hardik Prakash <[email protected]> merged to i2c/i2c-2. Thanks, Andi