On Mon, Mar 25, 2002 at 12:21:48PM +0000, Nick Craig-Wood wrote:
> The data stream gets corrupted in a very specific way - there are no
> bytes added or removed to the serial output but there is one byte
> overwritten with null (0x00) with 0,1 or 2 more corrupted bytes after
> it.
Ouch... that looks like a problem for non-cacheline-sized transfers. Does it
also happen with 48bytes?
> This was tested on a micro atx board with usb-uhci and this chipset.
> The same errors ocurr but less frequently with uhci instead of
> usb-uhci.
It's unlikely that both drivers make the same mistakes, especially this
one...
> 00:07.2 USB Controller: VIA Technologies, Inc. UHCI USB (rev 0a) (prog-if 00 [UHCI])
> Subsystem: Unknown device 0925:1234
The usual suspect...
> However (and this is what makes a simple bug report not so simple) the
> unpatched keyspan driver works absolutely perfectly on my desktop
> machine. On my laptop it doesn't give this error either but it spends
> so much time messing around in the BIOS with power management stuff
> that it is always dropping packets.
Intel makes the "best" UHCIs with the least flaws... We have discovered that
by the hard way. For our DAB monitoring system via USB (384KB/s ISO
streaming) we only use mainboards with Intel chipsets. We have tried VIA and
SiS in the beginning, but they weren't as reliable for USB as Intel
mainboards and caused much trouble for us and our customers... Especially
VIA seems to have great problems with PCI-arbitration, there is
significantly more lost data in the streamed data, and the "famous"
IDE+Soundblaster-bug speaks for itself...
> Does anyone have any more ideas as to what is going on or ideas as to
> what to try next?
If there's a BIOS that's worth mentioning, have you tried to play a bit with
the PCI settings (posted write, buffering, latency, etc)?
--
Georg Acher, [EMAIL PROTECTED]
http://www.in.tum.de/~acher/
"Oh no, not again !" The bowl of petunias
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