Hi, after a fair bit of looking I do not see a way to do a hard reset of a device. Windows seems to expose some functionality that hints these things are possible. Does anyone know if it is and is implemented in the Linux drivers? I only find reference to automatic power management in /sys. The ioctl in the title (IOCTL_USB_HUB_CYCLE_PORT) is joined by others that seem to actually control the power to the port. I recently saw patches that would control hub power state via additional hardware. It would be good to have a uniform way for userspace to take advantage of this power control. Userspace may have further hints that can be applied to power consumption, and may need to decide to undertake device recovery. What originally made me investigate this issue was a series of MCU development boards that crash needing power removed to recover. This seems to be impossible to do on most hardware. Why? There's no good reason to remove a complete power down from the spec. There are also instances where a hard reset for PCIe, e.g. cards malfunctioning when used with VFIO-VGA would have saved hardware from being hopelessly broken. So if you are involved in hardware design please consider these things. Cheers.
