ingle interrupter set, and it is a waste of time to check both registers when trying to figure out if the xHC interrupted or another device on the shared IRQ line interrupted. Only check the IP bit to reduce register reads. The IP bit is automatically cleared by the xHC when MSI or MSI-X is enabled. It doesn't make sense to read that register to check for shared interrupts (since MSI and MSI-X aren't shared). It also doesn't make sense to write to that register to clear the IP bit, since it is cleared by the hardware. We can tell whether MSI or MSI-X is enabled by looking at the irq number in hcd->irq. If it's -1, we know MSI or MSI-X is enabled. Signed-off-by: Sarah Sharp Signed-off-by: Greg Kroah-Hartman %Öò…–&x