On Monday, 20 August 2007 19:29, Pavel Machek wrote: > Hi! > > > > If I rmmod "ehci-hcd" then the power consumption is back to 69 W. This > > > confirms that this is really USB-related. I have to admit that I did > > > not expect an external drive to eat that much power from the system, > > > especially when not used. I am told that VIA chips are notoriously bad > > > at this kind of things. I'll try the same external drive on an Intel > > > system later today. > > > > > > The last mystery remaining is how USB "activity" can cause my CPU to > > > heat. I would expect the south bridge to heat, not the CPU. > > > > USB, or strictly speaking EHCI, OHCI and UHCI, use DMA. To allow > > that the cache coherency logic has to be active. Therefore your CPU > > cannot go to C3. Therefore it draws more power. The problem we are > > facing in USB is that to get great savings, our coverage has to be perfect. > > One device that cannot be autosuspended and we lose most savings. > > Ok.. but CONFIG_USB_SUSPEND should not really have anything to do with > CONFIG_SUSPEND (= s2ram). Perhaps it should depend on CONFIG_PM > instead?
CONFIG_USB_SUSPEND doesn't depend on CONFIG_SUSPEND. Greetings, Rafael - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
