On Sun, Dec 17, 2023 at 09:56:34PM -0600, Yinghua Yang Yang wrote: > Is there a way to set the auto suspend mode for a usb device without root > permission? I think this is a general question for many usb devices. > According to the Linux Kernel document > https://www.kernel.org/doc/Documentation/usb/power-management.txt, by > default the kernel disables autosuspend for all devices. So there are many > usb devices that support autosuspend but by default autosuspend is > disabled. In order to support autosuspend on those devices, are the only > solutions 1) obtain root permission and write ../power/control file using a > script It doesn't have to be a script; any sort of program can do it. A power-management daemon such as PowerTOP, for example. > 2) work with the hardware vendor on a driver/kernel to write the > autosuspend flag? That would be kind of silly. After all, if the vendor is willing to work with you on a kernel driver, they certainly ought to be willing to work with you on installing a power-management userspace program. And installing a program should be much easier than getting a new driver into the kernel. But to answer your question -- Yes, the only ways to modify the autosuspend settings are from userspace or from within the kernel. Alan Stern
