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From: David Brownell <david-b@pacbell.net>
To: "Lev A. Melnikovsky" <melnikovsky@mail.ru>
Cc: Alessandro Suardi <alessandro.suardi@gmail.com>,
	Rene Herman <rene.herman@keyaccess.nl>,
	linux-kernel@vger.kernel.org
Subject: Re: ehci-hcd affects hda speed
Date: Mon, 17 Mar 2008 13:06:52 -0800	[thread overview]
Message-ID: <200803171406.53241.david-b@pacbell.net> (raw)
In-Reply-To: <alpine.LFD.1.00.0803160054360.23451@nev.ubzr>

On Saturday 15 March 2008, Lev A. Melnikovsky wrote:
>  	Particularly, what does "MAC turn around 
> time" stand for with respect to EHCI? I would appreciate some reference, 
> thanks.

Blame VIA for that one.  Notice how their descriptions of the
fields in that register don't even mention a MAC.  :)

But the relevant bit is the "sleep time" and that's described
in the EHCI specification.  It basically means how long it waits,
after noticing a "no work for me" async schedule ring, before
scanning that schedule again.  It seems your system had that
set to just 1 usec, meaning it would hardly give anything else
a chance to get onto the PCI bus.  That's probably why the EHCI
spec uses a value of 10 usec:  basic fairness.

- Dave



  parent reply	other threads:[~2008-03-17 21:07 UTC|newest]

Thread overview: 36+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-03-04 22:27 Lev A. Melnikovsky
2008-03-05 16:19 ` Rene Herman
2008-03-05 20:03   ` Alessandro Suardi
2008-03-05 21:03     ` David Brownell
2008-03-06 16:25       ` Alessandro Suardi
2008-03-06 20:10       ` Lev A. Melnikovsky
2008-03-10 10:11         ` Lev A. Melnikovsky
2008-03-15 22:46           ` Lev A. Melnikovsky
2008-03-17 16:15             ` Alessandro Suardi
2008-03-17 21:06             ` David Brownell [this message]
     [not found]             ` <47DC596A.4010800@keyaccess.nl>
     [not found]               ` <200803171400.40045.david-b@pacbell.net>
2008-03-17 23:23                 ` Rene Herman
2008-03-17 23:26                   ` Rene Herman
2008-03-18  0:00                   ` David Brownell
2008-03-18  0:24                     ` Lev A. Melnikovsky
2008-03-18  1:27                       ` Rene Herman
2008-03-18  1:45                         ` David Brownell
2008-03-18  1:23                     ` Rene Herman
2008-03-18  1:55                       ` David Brownell
2008-03-18  3:13                         ` Rene Herman
2008-03-19 23:47                         ` Lev A. Melnikovsky
2008-03-20  0:31                           ` Rene Herman
2008-03-20  5:08                             ` Alessandro Suardi
2008-03-20 11:35                               ` Rene Herman
2008-03-20 21:01                                 ` Alessandro Suardi
2008-04-15 19:56                             ` Lev A. Melnikovsky
2008-04-15 20:02                               ` Oliver Neukum
2008-04-15 20:41                                 ` Lev A. Melnikovsky
2008-04-16  5:38                                   ` Oliver Neukum
2008-04-16 22:23                                     ` Lev A. Melnikovsky
2008-04-17  8:20                                       ` Oliver Neukum
2008-04-15 20:24                               ` Rene Herman
2008-04-15 20:32                               ` Rene Herman
2008-04-15 23:17                               ` David Brownell
2008-04-16 22:44                                 ` Lev A. Melnikovsky
2008-03-18 22:02                       ` Alessandro Suardi
2008-03-18 22:09                         ` Rene Herman

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