On Mon, 16 Aug 2010 09:38:42 -0400 (EDT), Alan Stern wrote:
> On Sun, 15 Aug 2010, Dennis Nezic wrote:
>
> > > As I said, your issue is very possible a hardware related, so
> > > recommend to do the compared(windows vs. linux) tests on
> > > same machine for ruling out hardware problem.
> >
> > I can't install MSWindows on my machine (for many reasons, money
> > being a big one), and it will take a little time before I get linux
> > installed on that other machine.
> >
> > However, I don't quite understand how you figure it's a hardware
> > issue. The device *clearly* works. Unless you think my laptop's USB
> > controller is broken? Which I *really* don't think it is, since I
> > use USB (2.0) storage devices on here all the time. Moreover, we
> > just saw how a simple /software/ modification yielded a quite
> > drastic change (reduction) in performance.
>
> Maybe the laptop's USB controller _and_ the storage device are both a
> little bit out-of-spec. Just enough so that they don't work with
> each other but they do work with other hardware. And just enough so
> that a slight variation in timing (introduced by a software change)
> can have a big effect on performance.
Gah. You're right! The drive works fine (at usb2 speeds / ehci) on my
other linux laptop (the one that had MSWindows previously)!?
So it works with:
00:1d.7 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW
(ICH6 Family) USB2 EHCI Controller (rev 04)
But not with:
00:13.2 USB Controller: ATI Technologies Inc IXP SB400
USB2 Host Controller
Why? :S
(From lspci -vvv:)
WORKS:
Linux 2.6.34-gentoo-r1 SMP i686 Intel(R) Pentium(R) M processor 1.86GHz
GenuineIntel GNU/Linux,
00:1d.7 USB Controller: Intel Corporation 82801FB/FBM/FR/FW/FRW
(ICH6 Family) USB2 EHCI Controller (rev 04) (prog-if 20 [EHCI])
Subsystem: Toshiba America Info Systems Device ff10
Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop-
ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz- UDF- FastB2B+ ParErr-
DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 0
Interrupt: pin A routed to IRQ 10
Region 0: Memory at f4000000 (32-bit, non-prefetchable) [size=1K]
Capabilities: [50] Power Management version 2
Flags: PMEClk- DSI- D1- D2- AuxCurrent=375mA
PME(D0+,D1-,D2-,D3hot+,D3cold+)
Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
Capabilities: [58] Debug port: BAR=1 offset=00a0
Kernel driver in use: ehci_hcd
DONTWORK:
Linux crixa 2.6.35.1 PREEMPT x86_64 AMD Turion(tm) 64 Mobile Technology
ML-30 AuthenticAMD GNU/Linux,
00:13.2 USB Controller: ATI Technologies Inc IXP SB400
USB2 Host Controller (prog-if 20 [EHCI])
Subsystem: Acer Incorporated [ALI] Device 007e
Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV+
VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx-
Status: Cap+ 66MHz+ UDF- FastB2B+ ParErr-
DEVSEL=medium >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
Latency: 64, Cache Line Size: 32 bytes
Interrupt: pin A routed to IRQ 19
Region 0: Memory at c0002000 (32-bit, non-prefetchable) [size=4K]
Capabilities: <access denied>
Kernel driver in use: ehci_hcd
Kernel modules: ehci-hcd
Non-verbose dmesg output from the working Intel laptop:
http://dennisn.dyndns.org/guest/pubstuff/ehci-bug/works-on-other-laptop.log
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