Hi Kurt, On Sat, Feb 8, 2025, at 8:54 AM, Kurt Borja wrote: > On Sat Feb 8, 2025 at 11:26 AM -05, Mark Pearson wrote: >> Thanks Kurt, >> >> On Fri, Feb 7, 2025, at 11:56 PM, Kurt Borja wrote: >>> Hi Mark, >>> >>> On Sat Feb 8, 2025 at 4:14 AM -05, Mark Pearson wrote: >>>> When reviewing and testing the recent platform profile changes I had >>>> missed that they prevent the tpacpi platform driver from registering. >>>> This error is seen in the kernel logs, and the various tpacpi entries >>>> are not created: >>>> [ 7550.642171] platform thinkpad_acpi: Resources present before probing >>> >>> This happens because in thinkpad_acpi_module_init(), ibm_init() is >>> called before platform_driver_register(&tpacpi_pdriver), therefore >>> devm_platform_profile_register() is called before tpacpi_pdev probes. >>> >>> As you can verify in [1], in the probing sequence, the driver core >>> verifies the devres list is empty, which in this case is not because of >>> the devm_ call. >>> >>>> >>>> I believe this is because the platform_profile driver registers the >>>> device as part of it's initialisation in devm_platform_profile_register, >>>> and the thinkpad_acpi driver later fails as the resource is already used. >>>> >>>> Modified thinkpad_acpi so that it has a separate platform driver for the >>>> profile handling, leaving the existing tpacpi_pdev to register >>>> successfully. >>> >>> While this works, it does not address the problem directly. Also it is >>> discouraged to create "fake" platform devices [2]. >>> >>> May I suggest moving tpacpi_pdriver registration before ibm_init() >>> instead, so ibm_init_struct's .init callbacks can use devres? >>> >> >> Yep - you're right. Moving it before the init does also fix it. >> >> I can't see any issues with this approach, but I'll test it out a bit more carefully and do an updated version with this approach. > > Thinking about it a bit more. With this approach you should maybe create > the tpacpi_pdev with platform_create_bundle() (I'm pretty sure you can > pass a NULL (*probe) callback) to avoid races. > > platform_create_bundle() only returns after the device has been > successfully bound to the driver. > Unfortunately having a null probe callback doesn't work - you end up with an oops for a null pointer dereference. Thanks Mark
