echo 1 > /sys/bus/usb/drivers/usb/bind Will bind it again. The side effect of unbind+bind is usb bus/device reset, depending on whether you are addressing bus or device
The number(s) being echoed means: usbBusNo usbPort usbDevice Check the bus/device format in /sys or dmsg or .... There is old article from GKH about how this worked in 2.6 kernels ages ago. It has changed somewhat and improved - see usb kernel sub-system documentation or google for more details. https://lwn.net/Articles/143397/ I am typing this on my cell, using google and memory - I was not able to verify current format on my system at home and I use remote multi-user centOS at work (cannot mess with that) Good luck, -T On Tue, Jan 23, 2024, 11:24 Vince Winter <[email protected]> wrote: > It is also about the power draw on the processor power and the system power > from having a USB controller working. Having any USB plugged adds > noticeable amount of power. > > I am hoping that telling the kernel, as per the suggestions here, to > unpower it that the controller goes back to "sleep mode". Also it would be > convenient if can I bring the device backup with out unplugging it. > > When I have a moment at work, I will get some empirical data if this works > or not. > > On Tue, Jan 23, 2024, 5:51 AM Tomas Kuchta <[email protected]> > wrote: > > > On Tue, Jan 23, 2024, 01:00 Ted Mittelstaedt <[email protected]> > > wrote: > > > > > I've messed with this before trying to troubleshoot USB cams. > > > > > > It's highly dependent on the USB hardware. Not all USB devices > implement > > > "low power" mode. > > > > > > Your best shot is to get a good USB 4 port hub - not a crappy one - a > > good > > > one and the good ones > > > Implement power control and can cut power to a USB device if you > command > > > them to. > > > . > > > > > > This is not about how the USB devices (mis)behave. They would not be > trying > > to control the devices, but the USB host(s) in the PC/laptop, I presume. > > > > USB host can, and will cut power to the bus when directed. > > > > While I am as guilty as any man - the world really sucks when people who > > think they understand stuff speak with undoubted authority about stuff. > > > > Hole it helps, -T > > > > > > > >
