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Not all boards have the interrupt output from the switch connected to a GPIO line. In such cases, phylib has to poll the internal PHYs, rather than receive an interrupt when there is a change in the link state. phylib polls once per second, and per PHY reads around 4 words. With a switch typically having 4 internal PHYs, this means 16 MDIO transactions per second. Rather than performing this phylib level polling, have the driver poll the interrupt status register. If the status register indicates an interrupt condition processing of interrupts in the same way as if a GPIO was used. Polling 10 times a second places less load on the MDIO bus. But rather than taking on average 0.5s to detect a link change, it takes less than 0.05s. Additionally, other interrupts, such as the watchdog, ATU and VTU violations will be reported. Signed-off-by: Andrew Lunn <andrew@lunn.ch> Signed-off-by: David S. Miller <davem@davemloft.net>
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.