Re: [PATCH 0/7] HID: picoLCD updates

On Wed, 15 Aug 2012, Bruno Prémont wrote:

quoted

I see. Alan Stern has fixed a huge pile of things in this area in 3.6-rc1. 
I have expected all of those to actually be on theoretical problems not 
ever having happened in the wild, but it might be that you are actually 
chasing on of those.

Could you please retest with latest Linus' tree (or at least eb055fd0560b) 
to see whether this hasn't actually been fixed already by Alan's series?

I've started trying that out, it seems Alan's work improved things.

For the first few attempts I have not seen SLAB corruptions, though after
a few rounds I hit accumulation of the following messages:
[  297.174828] hid-picolcd 0003:04D8:C002.0003: output queue full
[  297.181098] hid-picolcd 0003:04D8:C002.0003: output queue full
[  297.187820] hid-picolcd 0003:04D8:C002.0003: output queue full
[  297.194087] hid-picolcd 0003:04D8:C002.0003: output queue full

with sporadically in between:
[  292.668019] hid-picolcd 0003:04D8:C002.0003: usb_submit_urb(out) failed: -1

At first glance I think the queue filling up and never draining is caused
by hid_hw_stop() stalling the queue and the time between both being just too
short.

I don't really understand this explanation. Once usb_kill_urb() returns, 
the URB should be available for future use (and therefore all queues 
completely drained).

-- 
Jiri Kosina
SUSE Labs