The lan8814 represents a package of 4 PHYs. All of them are sharing the same interrupt line. So when a link was going down/up or a frame was timestamped, then the interrupt handler of all the PHYs was called. Which is all fine and expected but the problem is the way the handler interrupt works. Basically if one of the PHYs timestamp a frame, then all the other 3 PHYs were polling the status of the interrupt until that PHY actually cleared the interrupt by reading the timestamp. The reason of polling was in case another PHY was also timestamping a frame at the same time, it could miss this interrupt. But this is not the right approach, because it is the interrupt controller who needs to call the interrupt handlers again if the interrupt line is still active. Therefore change this such when the interrupt handler is called check only if the interrupt is for itself, otherwise just exit. In this way save CPU usage. Signed-off-by: Horatiu Vultur <horatiu.vultur@microchip.com> Link: https://lore.kernel.org/r/20230104194218.3785229-1-horatiu.vultur@microchip.com Signed-off-by: Jakub Kicinski <kuba@kernel.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.
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