[etherlab-dev] BUG in the mailbox handling

[Jun Yuan]

Hi,

as Gavin Lambert already mentioned one year ago, see
http://lists.etherlab.org/pipermail/etherlab-dev/2013/000327.html.

I checked the log of an industrial EtherCAT application I made, and I was
shocked to discover how deeply and frequently my application is affected by
this issue. It doesn't only affect those who use FoE, SoE, etc, it also
makes problem while only CoE is used. It doesn't not only affect when the
user application is started, but also show its teeth without any
application.

Scenario 1: CoE, no user application
One slave on the bus with 7 slaves is turned off for temporary maintenance.
After 5 - 30 seconds, it's turned on again. =>

[ 4629.242295] EtherCAT ERROR 0-0: Received unknown response while
uploading SDO 0x1C12:00.
[ 4629.242297] EtherCAT DEBUG: 00 80 07 00 00 00 11 00 09 06
[ 4629.242305] EtherCAT ERROR 0-0: Failed to read number of assigned PDOs
for SM2.

Cause: SDO dictionary fetch was disrupted as the slave comes up.
Consequence: User application cannot be started later, as no PDO was
assigned to SM2.


Scenario 2: CoE, with user SDO operation
Soon after all the slaves become online, the user application is started,
which read/write several SDOs from the slaves. And most of the sdo
operations fail.

[ 1169.599680] EtherCAT DEBUG 0-0: Uploading SDO 0x10F3:02.
[ 1169.607575] EtherCAT ERROR 0-0: Received unknown response while
uploading SDO 0x10F3:02.
[ 1169.607609] EtherCAT ERROR 0-0: Failed to process SDO request.
[ 1169.615791] EtherCAT DEBUG 0-0: Invalid entry description response while
fetching SDO entry 0x4810:08!
[ 1169.615852] EtherCAT DEBUG 0-0: Downloading SDO 0x10F3:03.
[ 1169.626209] EtherCAT DEBUG 0-0: Invalid SDO download response!
Retrying...
[ 1169.628254] EtherCAT DEBUG 0-0: Invalid entry description response while
fetching SDO entry 0x4810:09!
[ 1169.628336] EtherCAT DEBUG 0-0: Uploading SDO 0x10F3:27.
[ 1169.638630] EtherCAT ERROR 0-0: Received unknown response while
uploading SDO 0x10F3:27.
[ 1169.665583] EtherCAT DEBUG 0-0: Invalid entry description response while
fetching SDO entry 0x4810:0A!
[ 1169.665852] EtherCAT DEBUG 0-0: Uploading SDO 0x608F:01.
[ 1169.675979] EtherCAT ERROR 0-0: Received unknown response while
uploading SDO 0x608F:01.
[ 1169.684240] EtherCAT DEBUG 0-0: Invalid entry description response while
fetching SDO entry 0x4810:0B!

Cause: User SDO operation happens simultaneously with the SDO dictionary
fetch.
Consequence: User application has to be aborted.

Now I would consider it as a serious bug in the IgH EtherCAT Master, which
prevents the application to be successfully started every time. I'd like to
ask for the opinions/comments from the developers.

Regards,
Jun Yuan
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