RE: [PATCH] IB/mlx5: give back valid speed/width even without plugged in SFP module

[Parav Pandit]

> -----Original Message-----
> From: Hal Rosenstock [mailto:hal@xxxxxxxxxxxxxxxxxx]
> Sent: Friday, October 27, 2017 3:19 PM
> To: Parav Pandit <parav@xxxxxxxxxxxx>; Thomas Bogendoerfer
> <tbogendoerfer@xxxxxxx>; Matan Barak <matanb@xxxxxxxxxxxx>; Leon
> Romanovsky <leonro@xxxxxxxxxxxx>; Doug Ledford <dledford@xxxxxxxxxx>;
> linux-rdma@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx
> Cc: Ghazale Hosseinabadi <ghazale.hosseinabadi@xxxxxxxxxx>
> Subject: Re: [PATCH] IB/mlx5: give back valid speed/width even without plugged
> in SFP module
> 
> On 10/27/2017 2:32 PM, Parav Pandit wrote:
> > However I believe that ibstat tool should be enhanced to report unknown port
> speed instead of expecting drivers to supply some random number like this.
> 
> ibstat gets the rate from libibumad via /sys/class/infiniband/<IB
> device>/ports/<port number>/rate file which is supposed to be populated by the
> driver. Is there no rate file in this error case ?
> 
<...>/<port_num>/rate file exist.

rate_show() has invalid active_width as expected due to nonexistence of SFP.
So sysfs call return invalid value.
We don't have invalid_active_width defined right now.
So ibstat and other applications should not crash on such valid errors.