About PCAN-USB issues

[Stephane Grosjean <s.grosjean@peak-system.com>]

Hello all,

I'm finally back to the linux-can... I'm currently working on several 
projects so the peak_usb did progress slowly these last days...

Back to the issue: I changed the way the can state is handled in the 
peak_usb driver and finally get an easy tesbed to create bus-off 
events... Now, the driver puts the candev into that state only once, no 
more periodic error-warnings or else. I'm looking now to how the restart 
mechanism works.

1st: since the restart can be automatic, the related do_set_mode 
callback is called from a timer context, in which you're not allowed to 
sleep. So I suppose this is the reason of some Kernel hangs you (Oliver) 
detected last week: the peak_usb driver (tries to) reset the device by 
sending an usb message, using usb_bulk_msg(), which usage is not allowed 
in such a context! To confirm, is someone able to do the same with the 
ems_usb driver, please? It seems that this driver acts as the peak_usb does.

Moreover, it seems that the "manual" restart is also called from such a 
timer context, so the consequences are the same...

I'll have to change the way that reset is done into full asynchronous mode.

Regards,

Stéphane

--
PEAK-System Technik GmbH, Otto-Roehm-Strasse 69, D-64293 Darmstadt 
Geschaeftsleitung: A.Gach/U.Wilhelm,St.Nr.:007/241/13586 FA Darmstadt 
HRB-9183 Darmstadt, Ust.IdNr.:DE 202220078, WEE-Reg.-Nr.: DE39305391 
Tel.+49 (0)6151-817320 / Fax:+49 (0)6151-817329, info@peak-system.com