From mboxrd@z Thu Jan  1 00:00:00 1970
From: "Max S." <max@schneidersoft.net>
Subject: Re: GS_USB
Date: Fri, 15 Nov 2013 10:39:59 +0000
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To: Oliver Hartkopp <socketcan@hartkopp.net>
Cc: "linux-can@vger.kernel.org" <linux-can@vger.kernel.org>, Wolfgang Grandegger <wg@grandegger.com>

Hello all,

I've been doing some more testing and came across some strange behavior.
Frames appear to be out of order.

I have both chanels of the GS_USB device and a PEAKUSB adapter on a bus,
as well as another node (to ack frames).

I have modified the GS_USB firmware to PANIC when txed frames are out of
sequence.

tx interrupt now looks something like this

static uint8_t count = 0;
void tx_channel_0_interrupt(void){
	PANIC(txframe.data[0] != count);
	count++;

The GS_SUB device never panics, however cansequence -r on the peak
device gives me messages like:

received wrong sequence count. expected: 216, got: 220
received wrong sequence count. expected: 224, got: 216
received wrong sequence count. expected: 220, got: 224
received wrong sequence count. expected: 227, got: 229
received wrong sequence count. expected: 233, got: 227
received wrong sequence count. expected: 229, got: 233

notice that no frames are lost, just rearranged.

I can force frames to be out of order by restarting cansequence, so i
know my monitor code is working.

I have been trying to reproduce this error using libusb in userspace,
but have not had any success.

Any thoughts on this?

Regards,
Max Schneider.