From mboxrd@z Thu Jan  1 00:00:00 1970
From: Wolfgang Grandegger <wg@grandegger.com>
Subject: Re: pch_can: Data transmission stops after dropped packet
Date: Fri, 23 Nov 2012 18:00:33 +0100
Message-ID: <50AFABB1.7080507@grandegger.com>
References: <loom.20121114T160521-534@post.gmane.org> <loom.20121119T155735-163@post.gmane.org> <50AA4FB3.7070009@grandegger.com> <loom.20121119T171647-35@post.gmane.org> <50AA5EE6.6060105@grandegger.com> <loom.20121119T183819-427@post.gmane.org> <50AA86DB.7000506@grandegger.com> <loom.20121119T211403-520@post.gmane.org> <50AAA8C8.2080504@grandegger.com> <loom.20121120T151831-134@post.gmane.org> <50ABABDE.8060503@grandegger.com> <loom.20121120T192159-770@post.gmane.org> <50ABF09C.8040303@grandegger.com> <50ACABE2.2020306@grandegger.com> <loom.20121121T160744-278@post.gmane.or  g> <loom.20121121T162041-774@p  ost.gmane.org> <50ACF9C0.8050206@grandegger.com> <loom.20121121T170446-911@post.gmane.org> <50AD042B.3020305 @grandegger.com> <loom.20121121T184014-391@post.gmane.org> <50AD319E.200020
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To: Michael Pellegrini <mikep86@gmail.com>
Cc: linux-can@vger.kernel.org

On 11/23/2012 04:04 PM, Michael Pellegrini wrote:
> Wolfgang Grandegger <wg <at> grandegger.com> writes:
> 
>> Did you see any other related kernel messages? For real testing you
>> should remove the debug message above. I will try to add a more
>> sophisticated trigger.
> 
> I didn't see any other messages.  That message prints in such a tight
> loop that it's hard to catch any other messages.

That's clear. Therefore please remove that printk for testing. For a
quick test could you please add spin_locks to c_can_do_rx_poll() similar
to c_can_do_tx(). My suspicion is that there is a race in accessing the
message ram. There is this infamous c_can_msg_obj_is_busy() in
c_can_object_get() and c_can_object_put().

Wolfgang.