Re: [PATCH] nvme: determine the number of IO queues

[Minwoo Im]

On 4/18/19 9:52 PM, Aaron Ma wrote:
> On 4/18/19 8:13 PM, Minwoo Im wrote:
> > > Yes the IO queues number is 0's based, but driver would return error and
> > > remove the nvme device as dead.
> >
> > IMHO, if a controller indicates an error with this set_feature command,
> > then
> > we need to figure out why the controller was returning the error to host.
> >
> > If you really want to use at least a single queue to see an alive I/O
> > queue,
> > controller should not return the error because as you mentioned above,
> > NCQA, NSQA will be returned as 0-based. If an error is there, that could
> > mean that controller may not able to provide even a single queue for I/O.
>
> I was thinking about try to set 1 I/O queue in driver to try to probe
> NVME device.
> If it works, at least system can bootup to debug instead of just remove
> NVME device and kernel boot hang at loading rootfs.

If the controller returns error for that command, how can we assure that
the controller would support a single I/O queue ?

> If you still concern this 1 I/O queue I can still set it as
> *count = 0;
>
> At least we try all count, NVME device still failed to respond.
>
> Regards,
> Aaron
>
> > Thanks,
> > Minwoo Im