[ros-users] camera1394 - failure to start cameras

[Jack O'Quin]

On Mon, Jul 12, 2010 at 2:35 PM, Eric Perko <wisesage5001 at gmail.com> wrote:
> It seems kinda odd to introduce another parameter for whether or not to
> retry. Seems to me like retrying two or 3 times if the openCamera call fails
> the first time would be desirable in all cases (as long as certain parameter
> combinations don't actually damage the hardware). I'm just not sure what
> reason we would have for not trying again if the first try fails...

Mostly I'm just reluctant to make pervasive changes late in the test cycle.

How about adding a "retries" parameter that defaults to zero (current
behavior), but allows users to request one or more retries when an
open fails, before giving up? There would need to be a reasonable
upper limit to avoid hanging the driver node (maybe 3 or 7).

Then, Kim could start the driver like this:

 $ rosrun camera1394 camera1394_node _retries:=1

Alternatively, we could make the default be one or two retries, but
people could set it to zero if some device reacts badly. (I agree that
seems unlikely, but you never know).

> On Mon, Jul 12, 2010 at 3:12 PM, Kim Houck <kim_houck at yahoo.com> wrote:
>>
>> Dynamic Reconfigure would help, as it would eliminate the need to
>> shutdown nodes and/or rerun the launch file or rosrun command, but it
>> still would add an extra step on startup to make sure the cameras
>> started correctly.  But then again, it would be less likely to cause
>> problems with other camera hardware for an issue that sounds like it is
>> relatively obscure(although it sounds like odd behavior from 1394
>> cameras is not unheard of).

My experience with 1394 cameras is relatively limited. Just because I
have not seen this happen does not necessarily make it "obscure".

That's why we have alpha testers. :-)

I understand the importance of starting the camera without requiring
human intervention. I intend to fix this the problem once we converge
on a good solution.

Further thoughts, suggestions or ideas?
-- 
 joq