From: Wolfgang Grandegger <wg@grandegger.com>
To: Hui Wang <jason77.wang@gmail.com>
Cc: mkl@pengutronix.de, shawn.guo@linaro.org, linux-can@vger.kernel.org
Subject: Re: [RFC PATCH] can: dev: update rx state in the can_get_echo_skb()
Date: Thu, 28 Jun 2012 12:59:35 +0200 [thread overview]
Message-ID: <4FEC3917.5020905@grandegger.com> (raw)
In-Reply-To: <1340876540-27840-1-git-send-email-jason77.wang@gmail.com>
On 06/28/2012 11:42 AM, Hui Wang wrote:
> After a loopback packet is routed to rx interface, we forget to update
> rx state both in the can_get_echo_skb() and in the controller specific
> drivers, as a result, after we sent a loopback packet and executed
> ifconfig, following state is outputed:
> can0 Link encap:UNSPEC HWaddr 00-00-00-00-<snip>
> UP RUNNING NOARP MTU:16 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:1 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:10
> RX bytes:0 (0.0 B) TX bytes:4 (4.0 B)
>
> We add rx state update in the can_get_echo_skb() to solve this
> problem.
Well...
> Cc: linux-can@vger.kernel.org
> Cc: Marc Kleine-Budde <mkl@pengutronix.de>
> Cc: Wolfgang Grandegger <wg@grandegger.com>
> Cc: Shawn Guo <shawn.guo@linaro.org>
> Signed-off-by: Hui Wang <jason77.wang@gmail.com>
> ---
> I don't know if it is designed like that on purpose, please instruct
> me if i am wrong.
>
> I use following commands to let flexcan to work in the loopback mode:
> %>ip link set can0 type can bitrate 125000
> %>ip link set can0 type can loopback on
> %>ip link set can0 up
> And send a packet:
> %>cantest can0 123#AABBCCDD
> When i check net device state, i found tx doesn't equal rx:
> %>ifconfig
> can0 Link encap:UNSPEC HWaddr 00-00-00-00-<snip>
> UP RUNNING NOARP MTU:16 Metric:1
> RX packets:0 errors:0 dropped:0 overruns:0 frame:0
> TX packets:1 errors:0 dropped:0 overruns:0 carrier:0
This means that one message has successfully been sent to the *real* CAN
bus.
> collisions:0 txqueuelen:10
> RX bytes:0 (0.0 B) TX bytes:4 (4.0 B)
>
>>From my understanding, i suppose it should be:
> can0 Link encap:UNSPEC HWaddr 00-00-00-00-<snip>
> UP RUNNING NOARP MTU:16 Metric:1
> RX packets:1 errors:0 dropped:0 overruns:0 frame:0
> TX packets:1 errors:0 dropped:0 overruns:0 carrier:0
> collisions:0 txqueuelen:10
> RX bytes:4 (4.0 B) TX bytes:4 (4.0 B)
Why, you have not received any message from the CAN bus. If you want to
count looped back messages, it should be:
RX packets:1 errors:0 dropped:0 overruns:0 frame:0
TX packets:2 errors:0 dropped:0 overruns:0 carrier:0
Wolfgang.
next prev parent reply other threads:[~2012-06-28 10:59 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-06-28 9:42 [RFC PATCH] can: dev: update rx state in the can_get_echo_skb() Hui Wang
2012-06-28 10:59 ` Wolfgang Grandegger [this message]
2012-07-02 3:36 ` Hui Wang
2012-06-28 10:59 ` Kurt Van Dijck
2012-07-02 3:42 ` Hui Wang
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