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Re: cdrecord and "get performance" scsi errors



Giulio Orsero <giulioo@gmail.com> wrote:

> Linux 2.4.33
>
> Starting from 2.01.01a10 and this change:
>
>      * NEC drives incorrectly return CD speed values in mode page 2A.
>          * Try MMC3 get performance in hope that values closer to DVD speeds
>          * are always more correct than what is found in mode page 2A.
>
> I started getting the following errors on USB dvd writers (not on ide):
>  Input/output error. get performance: scsi sendcmd: no error
> CDB:  AC 00 00 00 00 00 00 00 00 64 03 00
>
> Joerg told me this was a Linux issue. I tried contacting Linux 2.4
> maintainer, but it was too difficult for me to follow this issue with him
> because I don't understand it. So I just gave up.
>
> Now I see a FreeBSD user got the very same error messages:
> http://lists.debian.org/cdwrite/2007/05/msg00009.html
>
> So, is this really a Linux issue? Do Linux and FreeBSD present the same bugs
> in the SCSI layer?
>
> I attach some logs, scgcheck was done with a disk always in since I'm not
> phisically near the writerto take it out.

> Profile: Removable Disk 
> ./cdrecord.test: Input/output error. get performance: scsi sendcmd: no error
> CDB:  AC 00 00 00 00 00 00 00 00 64 03 00
> status: 0x0 (GOOD STATUS)
> cmd finished after 0.004s timeout 200s

This is a hint for a bug in either the SCSI adaptation layer in libscg 
or a bug in the kernel.

As this problem is unknown with ATAPI over PATA, it may be a hint that
the ATAPI <-> USB adaptor is buggy.

IN order to better understand what happens, I would need more information
on what happens on FreeBSD at the CAM level in libscg.

Jörg

-- 
 EMail:joerg@schily.isdn.cs.tu-berlin.de (home) Jörg Schilling D-13353 Berlin
       js@cs.tu-berlin.de                (uni)  
       schilling@fokus.fraunhofer.de     (work) Blog: http://schily.blogspot.com/
 URL:  http://cdrecord.berlios.de/old/private/ ftp://ftp.berlios.de/pub/schily



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