On Thu, Mar 29, 2001 at 10:41:29AM -0500, Douglas Gilbert wrote:
> Bradley Broom wrote:
> > This appears to have something to do with tagged queueing on the disk drive.
> > If I disable tagged queueing for the disk, everything works fine. Note that
> > tagged queueing for the disk works ok when I mount the disk as a filesystem.
> >
> > However, both cdrecord and scanbus hang when writing an INQUIRY to /dev/sg0
> > (the scsi device corresponding to the disk). The system freezes either while
> > writing the INQUIRY command or *very* shortly thereafter. The test program I
> > wrote never gets so far as to issue the corresponding read.
> Bradley,
> There is a SCSI_IOCTL_TAGGED_DISABLE ioctl() supported by
> the SCSI mid level. So after opening a sg file descriptor
> and before sending an INQUIRY, you could try calling this
> ioctl().
>
> I am not confident that many adapter drivers take any notice
> of the Scsi_Device::tagged_queue flag, but it is worth a try.
> It is not obvious why sending a single INQUIRY which returns
> up to 256 bytes of data should be affected by the tagged
> queue settings. Do TEST UNIT READY commands work?
The driver does parse the return data of INQUIRY and sets its capabilities
accordingly. I guess something goes wrong when the user provides a large
buffer, so a SG list is used.
Patch sent to Bradley for testing ...
Regards,
--
Kurt Garloff <[EMAIL PROTECTED]> Eindhoven, NL
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