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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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