[vfio-users] Bus reset trouble with Titan-X

[Kevin Vasko]

Ah, ok. My bad.


Ran

#: setpci -s 3:00.0 82.w=8:8

SltSta: Status: AttnBtn- PowerFit- MRL- CmdCplt- PresDet+ Interlock-
            Changed: MRL- PresDet- LinkState-

#: setpci -s 3:00.0 78.w=20:20

StlSta: Status AttnBtn- PowerFlt- MRL- CmdCplt- PresDet+ Interlock-
           Changed: MRL- PresDet- LinkState-


When I run lspci -vvs 3:00.0 it is currently in this state

StlSta: Status AttnBtn- PowerFlt- MRL- CmdCplt- PresDet+ Interlock-
           Changed: MRL- PresDet- LinkState-

I didn't realize that I was needing to look at "PresDet", sorry. It does
look like it is different than before so I assume the setpci commands
changed it somewhere.

The device (GPU) is still in the "(rev ff) (prog-if ff)" state.

Do you think this could be a GPU issue? I have not tried a different GPU in
the system. Would it be worthwhile trying an NVidia M4000 to see if I get
the same results or do you think there is a problem with the PLX Riser?

Thanks,

-Kevin






On Wed, Oct 19, 2016 at 11:57 AM, Alex Williamson <
alex.williamson at redhat.com> wrote:

> On Wed, 19 Oct 2016 11:46:21 -0500
> Kevin Vasko <kvasko at gmail.com> wrote:
>
> > Alex,
> >
> > Thanks, but no luck.
> >
> > I ran :
> >
> > #:setpci -s 3:00.0 82.w=8:8
> >
> > checked
> >
> > #:lspci -vvvs 3:00.0
> >
> > MRL- was the same.
>
> PresDet+ on the Changed: line was the thing we were looking for.  MRL
> is a retention latch specifically for hotplug capable slots.
>
> > #: setpci -s 3:00.0 78.w=20:20
> >
> > checked:
> >
> > #: lspci -vvs 3:00.0
> >
> > MRL- was the same
> >
> >
> > LnkSta: Speed 2.5GT/s, Width x0, TrErr- Train- SlotClk- DLActive- BWMgmt-
> > ABWMgmt-
> >
> > SltSta: Status: AttnBtn- PowerFlt- MRL- CmdCplt- PresDet+ Interlock-
> >            Changed: MRL- PresDet+ LinkState-
> >
> > Just for my own knowledge what does "retrain" mean? I assume resetting
> the
> > bus and it reconnecting successfully?
>
> Retraining triggers a re-sync of the link width and speed parameters,
> think of it like kicking an Ethernet connection to renegotiate
> 10/100/1000Mbps speeds, a similar thing happens between a device and
> the downstream port that it's connected to to determine the link
> parameters.  Thanks,
>
> Alex
>
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