39b3666821
The host and the device can be connected with a called Wake-Up GPIO. When the host fall down this GPIO, it allows the device to enter in deep sleep and no communication with the device is no more possible (the device wakes up automatically on DTIM and fetch data if necessary). So, before to communicate with the device, the driver have to raise the Wake-up GPIO and then wait for an IRQ from the device. Unfortunately, old firmwares have a race in sleep/wake-up process and the device may never wake up. In this case, the IRQ is not sent and driver complains with "timeout while wake up chip". Then, the driver tries anyway to access the bus and an other error is raised by the bus. Fortunately, when the bug occurs, it is possible to fall down the IRQ and the device will eventually finish the sleep process. Then the driver can wake it up normally. The patch implements that workaround and add a retry limit in case something goes very wrong. Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com> Link: https://lore.kernel.org/r/20200825085828.399505-12-Jerome.Pouiller@silabs.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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.