Hi all, our research group is involved in building a large sensor node testbed, and we need to control the power supply of a number of USB devices by turning on/off the supply of the ports on the hub they are connected to. The hubs that we are using are DUB-H4, a self-powered 4-port USB 2.0 hub branded as D-Link, using a Genesys Logic controller.
Unfortunately, we are having problems with getting this to work with the more recent linux kernels and we don't have a record of the latest working ehci driver version. I would be grateful for any hints about potential changes in the drivers (in the last 5-6 months) that could have influenced the power control capability. Here is some debugging information: Bus 001 Device 002: ID 05e3:0660 Genesys Logic, Inc. Sending a control message to read the hub descriptor (using usb_control_msg from libusb), with enabled usbfs_snoop in the usbcore module returns: usb 1-3: usbdev_ioctl: CONTROL usb 1-3: control read: bRequest=06 bRrequestType=a0 wValue=0000 wIndex=0000 usb 1-3: control read: data 09 29 04 e9 00 32 64 00 ff According to table 11.23.2.1 in the USB 2.0 spec. "e9" says that the hub supports individual port power switching and over-current reporting. Checking the status of port-1 on the hub after the initialisation shows: usb 1-3: usbdev_ioctl: CONTROL usb 1-3: control read: bRequest=00 bRrequestType=a3 wValue=0000 wIndex=0001 usb 1-3: control read: data 00 01 00 00 and the same with a device connected: usb 1-3: usbdev_ioctl: CONTROL usb 1-3: control read: bRequest=00 bRrequestType=a3 wValue=0000 wIndex=0001 usb 1-3: control read: data 03 01 00 00 If we now send a command to turn off the power of port-1: usb 1-3: control write: bRequest=01 bRrequestType=23 wValue=0008 wIndex=0001 usb 1-3: control write: data: the port-1 status changes into power-down state: usb 1-3: control read: bRequest=00 bRrequestType=a3 wValue=0000 wIndex=0001 usb 1-3: control read: data 00 00 00 00 Unfortunately the power (in electrical terms) is still on and the LED indicator remains lit. With the older kernels, at this point of time, the LED was turned off and the power was disconnected. Also, with the recent kernels, the hub behaves differently when the external power is disconnected while the hub remains connected to the host controller. Previously, this has resulted in all ports going into power-down state. Now, after a short reset, the hub is re-powered from the bus. Could it be that the same thing is happening when we want to turn the individual ports, i.e. the driver thinking that this is an error condition and trying corrective actions in the background? Best regards, Vlado Handziski TU Berlin P.S. I apologize if this is a duplicate, the system rejected my original mail because of the HTML that gmail inserts. ------------------------------------------------------- SF.Net email is Sponsored by the Better Software Conference & EXPO September 19-22, 2005 * San Francisco, CA * Development Lifecycle Practices Agile & Plan-Driven Development * Managing Projects & Teams * Testing & QA Security * Process Improvement & Measurement * http://www.sqe.com/bsce5sf _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
