[Devel] Re: unexpected scsi timeout

[Vasily Averin]

Albert Lee wrote:
>>> Vasily Averin wrote:
>>>> I've noticed that some scsi commands for DVD-drive attached to pata_via
>>>> successfully finishes without any delays but reports about TIMEOUT condition. It
>>>> happens because of ATA_ERR bit is set in status register. As result for each
>>>> command  Error Handler thread awakened, requests sense buffer and go to sleep again.
>>> Need more info.  Please post boot dmesg and the result of 'lspci -nn'
>>> and 'hdparm -I /dev/srX' and when such errors occur.
> 
> Your log looks ok. It's normal for TEST_UNIT_READY to return ATA_ERR when no disc
> inside and libata EH triggered to request sense.

It's a bit strange for me, IMHO other scsi drivers requests sense buffer without
EH thread assistance.
Currently we know that ATA_ERR can be returned; it is not error, but one of
expected responses. Why we cannot request sense without EH? I would like to
understand is it implementation drawback or I missed something probably?

Thank you,
	Vasily Averin