Closed mypiandrew closed 6 years ago
Some device drivers in kernel are surprised by USB device being turned off and automatically try to power it back on. You can use option -r N
where N is some number from 10 to 100 to fix this - uhubctl will try to turn power off many times in quick succession, and it should suppress that. This may be eventually fixed in kernel, see more discussion here: https://www.spinics.net/lists/linux-usb/msg157413.html
Hi
Yes adding -r 80 appears to force it :)
Good, I'm glad you have working solution - this is why I added this option. I wish Linux kernel developers improved support for power control in kernel... BTW, using -r should not be necessary on Mac or FreeBSD.
Using a custom Rasberry Pi board with LAN9512 device, As per the reference design we have used a MIC2026 device to gate the +5V power feed to the USB ports, which is controlled by the PRTCTL2/3 lines (see page 17 of LAN9512 chip for details)
When using your neat program I find that setting a port off causes port power to cycle on-off-on (rather than stay off)
What am I missing here ?
dmesg shows :
How do I make "no" mean "no" here (i.e. make the power off mean OFF)