Re: PROBLEM: USB keyboards works only 4 per PC host port
From: Alan Stern
Date: Tue Aug 19 2008 - 16:04:58 EST
On Tue, 19 Aug 2008, David Brownell wrote:
> The OHCI scheduling is pretty simple and compact. I'd think it would
> be easy enough to make UHCI do the same sort of thing: track bandwidth
> assigned to 2^N frames (OHCI hardware imposes a smaller limit for N
> than UHCI hardware does), and pick the least loaded of those frames to
> use for new transfers. In ohci-q.c see balance(), periodic_{,un}link().
>
> Thing is that would involve changing how UHCI manages periodic transfers;
> assuming it hasn't changed those structures since last I looked.
Yes. That's the messy part; the scheduling itself is easy.
Alan Stern
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