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    SubjectRe: ehci-hcd affects hda speed
    On Sat, Mar 15, 2008 at 11:46 PM, Lev A. Melnikovsky
    <> wrote:
    > LAM> Also, does anyone have a VT6212L datasheet? Unfortunately, Google
    > I have eventually found it. An enlightening reading, really. If I
    > understood all words, I mean :-). Particularly, what does "MAC turn around
    > time" stand for with respect to EHCI? I would appreciate some reference,
    > thanks.
    > On Wed, 5 Mar 2008 at 5:19pm, Rene Herman wrote:
    > RH> It was diagnosed to the VT6212L doing decidedly weird things with
    > RH> toggling the Async bit and tying up the bus.
    > Yes, it really looks like the chip owns the bus when it shouldn't. Suppose
    > VT6212L has damaged its brains somehow. Can we fix this by ignoring its
    > requests unless they are legitimate? I mean make the driver enable bus
    > mastering only for short periods when the controller is expected to do
    > something useful. It is easy (I have already done myself) to implement for
    > asynchronous schedule, but there's still periodic schedule. Is it
    > possible? How? Please advise.
    > Being positive, I didn't have much time to play with it yet, but changing
    > the bit 5 (EHCI sleep time select: 0=1us 1=10us) of register 0x4B seems
    > to resolve my own problem. I wonder if this is going to help others
    > (Alessandro?):
    > setpci -s 00:09.2 4b.b=29
    > [don't forget to adjust the device address].

    00:09.2 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 63)

    heh, I don't even have to...

    [root@donkey ~]# hdparm -t /dev/hda

    Timing buffered disk reads: 54 MB in 3.03 seconds = 17.83 MB/sec
    [root@donkey ~]# setpci -s 00:09.2 4b.b=29
    [root@donkey ~]# hdparm -t /dev/hda

    Timing buffered disk reads: 78 MB in 3.06 seconds = 25.53 MB/sec

    Well, that does look much better. Not on par with the non-EHCI case,
    but way better ! Thanks a lot !

    Of course if you wish me to run anything else, just say so :)


    "We act as though comfort and luxury were the chief requirements
    of life, when all that we need to make us really happy is
    something to be enthusiastic about."

    (Charles Kingsley)

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