I have developed a Driverkit extension which matches for iPadOS which is bundled within my app. My driver contains two different personalities - one with provider as USBDriverKit (USB3) and the other as PCIDriverKit (USB4). When enabled, the driver matches/loads, initiates the class with the right personality based on whether the device it matches is operating in USB3/USB4 and works as intended. Recently, we have come across an issue when operating in USB4 and below are the steps to reproduce.
Platform:
iPadOS 17 (Issue not observed following the same steps in iPadOS 18 and higher, though cannot be full sure as I have tested only in some versions of 18, 26 and 27). Tested in iPad having a USB-4 compatible port.
Steps to reproduce:
- Install the app. This provides an option to enable the driver which comes with it from the app's system settings.
- Enable the driver from settings.
- Connect a device which is compatible with the driver in USB4 so that the specific personality can be loaded. Verify the same.
- With the driver still loaded, uninstall the application.
On uninstallation, ideally, Apple's inbox IONVMeController should match on the re-enumeration and get loaded without a re-plug being required. However, this is not the case as the port becomes unresponsive. Even after a re-plug of the device, it still does not get detected by the iPad itself.
This is specifically when I try to connect the device in USB 4 as this specific driver personality matches only in this case. If I try the same steps as above or try to connect the same device in USB3 after this issue has occured, the device gets detected and works as intended. To make the port to be usable again in USB4, a restart of the iPad has to be performed.
Has this been observed before with PCIDriverKit or DriverKit in general? Is this some kind of a known limitation in iPadOS 17 in particular or does this have something to do with the iPad model too? Is there any workaround that can be followed to prevent this from happening?