On 11/21/2012 04:52 PM, Alan Stern wrote: > On Wed, 21 Nov 2012, Felipe Balbi wrote: > >> On Thu, Nov 15, 2012 at 04:34:14PM +0200, Roger Quadros wrote: >>> From: Andy Green <andy.green@xxxxxxxxxx> >>> >>> This patch changes the management of the two GPIO for >>> "hub reset" (actually controls enable of ULPI PHY and hub reset) and >>> "hub power" (controls power to hub + eth). >> >> looks like this should be done by the hub driver. Alan, what would you >> say ? Should the hub driver know how to power itself up ? > > Not knowing the context, I'm a little confused. What is this hub > you're talking about? Is it a separate USB hub incorporated into the > IP (like Intel's "rate-matching" hubs in their later chipsets)? Or is > it the root hub? > This is actually a USB HUB + Ethernet combo chip (LAN9514) that is hard wired on the panda board with its Power and Reset pins controlled by 2 GPIOs from the OMAP SoC. When powered, this chip can consume significant power (~0.7 W) because of the (integrated Ethernet even when suspended. I suppose the ethernet driver SMSC95XX) doesn't put it into a low enough power state on suspend. It doesn't make sense to power the chip when USB is not required on the whole (e.g. ehci_hcd module is not loaded). This is what this patch is trying to fix. cheers, -roger -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
