During the probe we add an I2C adapter and as soon as we add that adapter it may be used for a transfer (e.g via the code in i2cdetect()). Those transfers are not able to complete and time out. This is because the HID raw_event callback (mcp2221_raw_event) will not be invoked until the HID device's 'driver_input_lock' is marked up at the completion of the probe in hid_device_probe(). This starves the driver of the responses it is waiting for. In order to allow the I2C transfers to complete while we are still in the probe, start the IO once we have completed init of the HID device. This issue seems to have been seen before and a patch was submitted but it seems it was never accepted. See: https://lore.kernel.org/all/20221103222714.21566-3-Enrik.Berkhan@inka.de/ Signed-off-by: Hamish Martin <hamish.martin@alliedtelesis.co.nz> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Linux kernel ============ There are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. Please read Documentation/admin-guide/README.rst first. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. The formatted documentation can also be read online at: https://www.kernel.org/doc/html/latest/ There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. Please read the Documentation/process/changes.rst file, as it contains the requirements for building and running the kernel, and information about the problems which may result by upgrading your kernel.
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