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Date: Mon, 20 Nov 2000 13:37:23 +0100
From: Thomas Sailer <sailer@ife.ee.ethz.ch>
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To: Linus Torvalds <torvalds@transmeta.com>
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Subject: Re: test11-pre6 still very broken
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Linus Torvalds wrote:

> I'd disagree.  UHCI has tons of advantages, not the least of which is
> [Cthat it was there first and is widely available.  If OHCI hadn't been
> done we'd have _one_ nice good USB controller implementation instead of

UHCI has a couple of disadvantages, though (and some of them could have
been fixed with only very little added gates).

For example:

- one cannot reliably unlink transfer buffers from the queues without
  waiting 1ms
- bandwidth reclamation can be a real PCI hog

> I hope EHCI makes it all moot. Some way or another.

Only for USB2 devices. EHCI is supposed to be paired with an existing
UHCI or OHCI controller core that is supposed to take over the USB connector
if an USB 1.x hub or device is plugged in. So we end up needing to support
UHCI and OHCI for a very long time, I don't see mice and keyboards going
USB2 anytime soon 8-)

Tom
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