Putting a lid on USB power

Posted Jun 8, 2006 22:43 UTC (Thu) by ehovland (subscriber, #2284)
In reply to: Putting a lid on USB power by giraffedata
Parent article: Putting a lid on USB power

> What hardware is being run outside its specs?

I would say that the hub and the USB host controller are the two hardware devices that would be driven to power levels that they were not necessarily specified. Since they were the ones who were suffering the brunt of this issue in older kernels.

Although I doubt running the hub beyond power spec is a serious problem, running the usb host controller hardware out of spec could cause no end of problems that may be difficult to diagnose if it is drawing too much power.

Putting a lid on USB power

Posted Jun 9, 2006 2:00 UTC (Fri) by giraffedata (guest, #1954) [Link]

I thought the article was saying that Linux knows the capacity of the host USB controller hardware and therefore knows that it is within specs if the USB device is allowed to power up. Otherwise, what is the point of the device telling Linux how much current it needs?