Micha Nelissen wrote:

=20
Alexandre Bounine wrote:

quoted

Add check if PW message source device is accessible and change PW

message

quoted

handler to recover if PW message source device is not available

anymore (power

quoted

down or link disconnect).

=20
I am not quite sure what the point is of this patch. What do you need

to

recover from?

From failed maintenance read. In the previous version PW handler had

troubles if maintenance
read request fails. Now I am trying to detect lost or remover devices as
soon as I see broken link.

=20

quoted

To avoid possible loss of notification, the PW message handler scans

the route

quoted

back from the source device to identify end of the broken link.

=20
Do you mean if port-writes are dropped? Then they did not reach you in
the first place. If a link in between is broken, the associated switch
will 'complain' and send port-writes, no?

Situation that I am trying to resolve is mostly applicable to larger
systems that have multiple complex boards (or chassis/domains) connected
together. Power down sequence on the board (chassis) combined with
switch hierarchy may allow switch to send PW message to the host before
its power is off. This will create an orphaned PW message.=20
At the same time there is no guarantee that PW message from the
associated switch will reach the host.
That "real" PW message may be dropped by the controller (85xx is good
example). Everything depends on number of PW messages directed to the
host/controller. I am trying to use the first available notification to
service device removal. If the "real" PW message is received it should
be processed without any further action.=20

Alex.