On Wed, Apr 27, 2022 at 07:48:06AM +0200, Lukas Wunner wrote: > Cache the interrupt mask to avoid re-reading it from the PHY upon every > interrupt. The PHY may be located on a USB device, so the additional > read may unnecessarily increase interrupt overhead and latency. I don't think your justification is valid. The MDIO bus is clocked at 2.5MHz. So even if you are using USB 1.1 at 12MHz, the USB overheads are not particularly large. At 480Mbps they are pretty insignificant. In general, we consider PHYs as slow devices, they take over 1 second to negotiate a link and declare it up. So we don't do this sort of micro optimization. What i think is relevant here is that you could have an interrupt storm going on because you don't mask interrupts? It is not a true storm, due to the way USB works, more of a light shower. Do you have any statistics to show this code actually reduces the amount of rain in a significant way? Andrew
