[PATCH 5/7] can: clear ctrlmode when close candev
socketcan at hartkopp.net
Mon Nov 3 10:25:12 PST 2014
On 11/03/2014 05:28 PM, Marc Kleine-Budde wrote:
> On 10/29/2014 11:45 AM, Dong Aisheng wrote:
>> Currently priv->ctrlmode is not cleared when close_candev, so next time
>> the driver will still use this value to set controller even user
>> does not set any ctrl mode.
>> Step 1. ip link set can0 up type can0 bitrate 1000000 loopback on
>> Controller will be in loopback mode
>> Step 2. ip link set can0 down
>> Step 3. ip link set can0 up type can0 bitrate 1000000
>> Controller will still be set to loopback mode in driver due to saved
>> This patch clears priv->ctrlmode when the CAN interface is closed,
>> and set it to correct mode according to next user setting.
> Oliver, what do you think of this patch? It will introduce a subtle
> change to the userspace.
indeed the current policy is that ifdown/ifup doesn't change any setting.
When we start to clear priv->ctrlmode when setting the interface down the
question arises whether the bitrate(s) has/have to be wiped too.
Setting the interface down/up can be done with ip or ifconfig without changing
the controller settings.
So IMO we can not assume that people always use the 'all-in-one'
ip link set can0 up type can0 bitrate 1000000
command as given in the example above.
You might also do it like this:
ip link set can0 up type can0 bitrate 1000000 loopback on
ip link set can0 down
ip link set can0 type can0 loopback off
ip link set can0 up
Finally I would vote to reject this patch to stay consistent.
When users like to fiddle with options like loopback they need to take care
about their 'expert' settings too.
>> Signed-off-by: Dong Aisheng <b29396 at freescale.com>
>> drivers/net/can/dev.c | 1 +
>> 1 file changed, 1 insertion(+)
>> diff --git a/drivers/net/can/dev.c b/drivers/net/can/dev.c
>> index 02492d2..1fce485 100644
>> --- a/drivers/net/can/dev.c
>> +++ b/drivers/net/can/dev.c
>> @@ -671,6 +671,7 @@ void close_candev(struct net_device *dev)
>> + priv->ctrlmode = 0;
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