Adaptec 2940UW problem with CDRW Yamaha 6416 SCSI

Doug Ledford dledford at
Thu Oct 14 06:40:40 PDT 1999

On Thu, 14 Oct 1999, Roman Melnyk wrote:

> Hi,
>    Can anyone help me with the following problem.
> I have a Dell PII 350 PC with a Adaptec 2940 UW card and an external Yamaha 
> CDRW 6416 Drive.
> The problem is when LINUX loads the Adaptec driver (AIC7xxx.o) and scans 
> the SCSI bus for devices and it reaches the Yamaha drive, It resets the 
> drive and causes the Yamaha drive to hang. It then causes the LINUX driver 
> (AIC7xxx) to hang on that device and reports a device timeout. All the 
> other devices on the external SCSI bus works great. I have RedHat 6.0 
> installed. I have tried this on two different PC hardware with different 
> 2940 cards. The result is the same. The driver is sending something that 
> the Yamaha drive does not like and then hangs the drive. It is worth 
> mentioning that the drive under Windows 95 works great with the same 2940 
> and PC hardware. Although the Windows drive does not do the same reset on 
> the device at boot time as does the LINUX drive. I know that this Yamaha 
> drive is new and there maybe some compatibility issues. But it would be 
> nice to have it work under LINUX. Any help would be appreciated.

Hmmm...interesting timing.  And here is an exact example of why the Red
Hat Linux 6.1 kernel doesn't scan all LUNs by default.  The answer to your
problem is to either upgrade to the latest Red Hat Linux or at least grab
the kernel rpm from the 6.1 distro and install it on your machine
(following the instructions about upgrading your kernel via rpm, etc) and
the problem will go away.  If you simply want to compile your own kernel,
then you can do so and it should work as long as you leave the option
PROBE ALL LUNS in the SCSI config disabled.  The Yamaha CD-RW drives lock
up when probed with a lun higher than 0.

  Doug Ledford   <dledford at>
   Opinions expressed are my own, but
      they should be everybody's.

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