Sergij Kolisnyk wrote:
>
> ----- Original Message -----
> From: "Roman Weissgaerber" <[EMAIL PROTECTED]>
> To: <[EMAIL PROTECTED]>
> Sent: Wednesday, May 09, 2001 8:34 PM
> Subject: Re: [linux-usb-devel] EILSEQ - FAQ ??
>
> > > > Sergij Kolisnyk wrote:
> > > > >
> > > > > Hi!
> > > > >
> > > > > All we know the problem.
> > > > >
> > > > > On _some_ motherboards when doing USB bulk read at full speed,
> > > > > URB completes with "-84" error code...
> > > > >
> > > >
> > > > -84 (EILSEQ) means CRC Error of the packet sent by the device.
> > >
> > > Or timeout...
> > >
> > No!!!! EILSEQ means just CRC Error, ETIMEDOUT means timeout.
>
> IMHO ETIMEDOUT means _user_ timeout,
> specified in URB - really too many NAK's...
> What are codes for:
>
> 1) USB frame time (=1ms) overrun
> 2) PCI data transfer timeout
> 3) USB device response timeout (to host's polling)
>
Who cares? If you really want to now then look at the manual.
None of the error codes is EILSEQ here.
> IMHO UHCI reports same error code on (2) and CRC error
>
But for in transfers it reports only CRC error
(read the manual).
>From uhci.c:
if (status & TD_CTRL_CRCTIMEO) { /* CRC/Timeout */
if (dir_out)
return -ETIMEDOUT;
else
return -EILSEQ;
}
so EILSEQ is for in packets and means bad CRC.
- Roman
> > See Programming Guide for Linux USB Device Drivers, Page 26
> > Section 3.1, Error Codes!!!
> > See also kernel 2.4.4 uhci.c line 786 or usb-uhci.c line 2160 or
> > USB_ST_CRC (just CRC) for ohci.c (mapping is in usb.h).
> >
> > > > So I think this is a problem of the device and not of the HC.
> > >
> > > This is at least MB BIOS or VGA dependent!!!
> > > This is checked.
> > >
> > Or Power Supply or PCB Design ...
> >
> > > Same HD. So the same Linux. Same 440BX. Different BIOS.
> > > Different VGA (both nVidia). One of them has X running, one not.
> > >
> > > The error occured only on one of them.
> > >
> > > >
> > >
> > > And problem is reported by many people trying to utilyze
> > > full throughput avaliable in USB 1.1.
> > >
> >
> > Who has reported, Where has it been reported?
>
> Only here by Johan Verrept <[EMAIL PROTECTED]>
> and Gordon McNutt <[EMAIL PROTECTED]>
>
> Johan's report is old, Gordon's - few days ago.
>
> >
> > > Different devices are affected.
> > >
> >
> > What devices do you use.
> >
> > - Roman
> >
> > > When one of device or driver slowes the throughput down,
> > > the error disappears.
> > >
> > > MacOS drivers don't see the error at same speeds.
> > >
> > > > - Roman
> > > >
> > > >
> > > > > That happens only when device is fast enough to really utilyze
> > > > > throughput of USB 1.1 full speed.
> > > > >
> > > > > IMHO, this error may depend on BIOS, VGA and having X running...
> > > > > Error isn't HCI-specific, it occurs on both OHCI and UHCI.
> > > > >
> > > > > FAQ: How to workaround this error?
> > > > > May be usb.c has to have URB-wrapper to suppress the error?
> > > > > Isn't Linux overuse USB frame duration?
> > > > >
> > > > > I haven't found the answer anywhere...
> > > > >
> > > > > Thank you,
> > > > > Sergij Kolisnyk
>
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