Date: Tue, 04 Mar 2008 10:27:35 +0200 From: Andriy Gapon <avg@icyb.net.ua> To: Anish Mistry <amistry@am-productions.biz> Cc: freebsd-usb@freebsd.org Subject: Re: Suspend/Sleep/Stop USB device Message-ID: <47CD07F7.2080001@icyb.net.ua> References: <200803031654.31592.amistry@am-productions.biz>
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Anish,
I once played with a similar idea - to power off a USB port once a UMASS
device (attached to it) is unmounted, similarly to how windows does it.
I haven't reached any completely satisfactory results, but I got some
results. I have a very faint memory of that now, but I think that either
of the following two should work for a port of a USB hub device:
usbd_clear_port_feature(dev, port, UHF_PORT_ENABLE);
usbd_clear_port_feature(dev, port, UHF_PORT_POWER);
I actually issued the request from user-land, but I think that a proper
solution would be to add a new ioctl for this purpose and a proper
handling of it in usb/uhub.
This is a snippet of the userland code that I still have around:
if ((fd = open(device_name, O_RDWR, 0)) < 0) {
error("%s", device_name);
exit(EXIT_FAILURE);
}
/*==============================================================*/
ctlreq.ucr_addr = 1; /* XXX */
ctlreq.ucr_request.bmRequestType = UT_WRITE_CLASS_OTHER;
ctlreq.ucr_request.bRequest = UR_CLEAR_FEATURE;
USETW(ctlreq.ucr_request.wValue, UHF_PORT_POWER);
//USETW(ctlreq.ucr_request.wValue, UHF_PORT_ENABLE);
USETW(ctlreq.ucr_request.wIndex, 8); /* XXX */
USETW(ctlreq.ucr_request.wLength, 0);
ctlreq.ucr_data = 0;
ctlreq.ucr_flags = 0;
ctlreq.ucr_actlen = 0;
/*==============================================================*/
if (ioctl(fd, USB_REQUEST, &ctlreq) != 0) {
error("ioctl USB_REQUEST");
close(fd);
exit(EXIT_FAILURE);
}
--
Andriy Gapon
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