[Xenomai-core] Re: RT-CAN tx_sem

[Wolfgang Grandegger <wg@domain.hid>]

Jan Kiszka wrote:
> Hi Wolfgang,
> 
> fiddling with the CAN utils, I noticed the behaviour that rtcansend on
> freshly registered but stopped devices simply blocks. And when you
> meanwhile call rtcanconfig up on that device, rtcansend will continue to
> block.

This is a bug, the send function should return an error in that case.

> The reason is that during startup of CAN devices the tx-semaphore is
> re-initialised while it is already set up during device registration.
> Re-init on an already initialised rtdm_sem is, say, undefined.
> 
> So rtdm_sem should better only be initialised/destroyed by the drivers.
> Trying to send on a shut down CAN device could be catched differently,
> e.g. via the device state. This likely needs more thoughts, take it as a
> note that $something should be done.

I'm going to check this later today or tomorrow.

Wolfgang.