RE: Crazy USB Interrupts.

From: Dunlap, Randy (randy.dunlap@intel.com)
Date: Fri Mar 24 2000 - 18:14:47 EST

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    Yep. Georg already replied (to linux-usb@suse.com):

    <quote>
    The plan is to disable the interrupt TD when there are no unlinks nor
    URBs with timeout pending. The URB-timeout check was moved into the uhci
    interrupt, since that simplifies the locking.
    </quote>

    ~Randy
    ___________________________________________________
    |Randy Dunlap Intel Corp., DAL Sr. SW Engr.|
    |randy.dunlap.at.intel.com 503-696-2055|
    |NOTE: Any views presented here are mine alone |
    |and may not represent the views of my employer. |
    |_________________________________________________|

    > -----Original Message-----
    > From: Mark Hahn [mailto:hahn@coffee.psychology.mcmaster.ca]
    > Sent: Friday, March 24, 2000 3:11 PM
    > To: Dunlap, Randy
    > Cc: linux-kernel@vger.rutgers.edu; 'linux-usb@suse.com'
    > Subject: RE: Crazy USB Interrupts.
    >
    >
    > > The usb-uhci driver uses a lazy (delayed) TD
    > > cleanup method that is based on USB interrupts.
    >
    > dandy. so why are the interrupts continuing at HIGH RATE
    > when USB is *completely*idle*?
    >
    > > It's author/maintainer (Georg Acher) has been
    > > told about this behavior already. I'm not sure
    > > what his plans are.
    >
    > this needs to be fixed. I just measured the overhead of this
    > at 1-2% on my dual celeron/550. lots of people expect Linux to
    > run reasonably on machines with 1/10 this much power; I expect
    > this mis-feature costs 10-20% on a P5/166.
    >
    > regards, mark hahn.

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