Re: [PATCH v3] scsi: ufs: Cleanup completed request without interrupt notification

Bart Van Assche
2020-07-13T01:39:48Z

On 2020-07-06 06:21, Stanley Chu wrote:
> If somehow no interrupt notification is raised for a completed request
> and its doorbell bit is cleared by host, UFS driver needs to cleanup
> its outstanding bit in ufshcd_abort().

How is it possible that no interrupt notification is raised for a completed
request? Is this the result of a hardware shortcoming or rather the result
of how the UFS driver works? In the latter case, is this patch perhaps a
workaround? If so, has it been considered to fix the root cause instead of
implementing a workaround?

In section 7.2.3 of the UFS specification I found the following about how
to process request completions: "Software determines if new TRs have
completed since step #2, by repeating one of the two methods described in
step #2. If new TRs have completed, software repeats the sequence from step
#3." Is such a loop perhaps missing from the Linux UFS driver?

Thanks,

Bart.