Subject: Re: [PATCH] net: ethernet: cpsw: ignore VLAN ID 1

From: Felipe Balbi <[email-masked]>
Date: Tue, 6 Jan 2015 14:31:19 -0600

Hi,

On Tue, Jan 06, 2015 at 02:13:23PM -0500, David Miller wrote:
> From: Felipe Balbi <[email-masked]>
> Date: Tue, 6 Jan 2015 11:43:32 -0600
> 
> > CPSW completely hangs if we add, and later remove,
> > VLAN ID #1. What happens is that after removing
> > VLAN ID #1, no packets will be received by CPSW
> > rendering network unusable.
> > 
> > In order to "fix" the issue, we're returning -EINVAL
> > if anybody tries to add VLAN ID #1. While at that,
> > also filter out any ID > 4095 because we only have
> > 12 bits for VLAN IDs.
> > 
> > Fixes: 3b72c2f (drivers: net:ethernet: cpsw: add support for VLAN)
> > Cc: <[email-masked]> # v3.9+
> > Cc: Mugunthan V N <[email-masked]>
> > Tested-by: Schuyler Patton <[email-masked]>
> > Signed-off-by: Felipe Balbi <[email-masked]>
> 
> You can't just unilaterally make one VLAN ID unusable.
> 
> A better way to handle this situation must be found,
> and if that means turning off hw VLAN support completely,
> that's a much better alternative to this.
> 
> I'm not applying this patch, sorry.

All other IDs work alright, it's just ID 1 which seems to be quirky. In
fact when trying to add VLAN ID 1, vconfig itself dumps out a warning
that VLAN ID 1 doesn't work on most switches.

What you're saying here is that you prefer to drop a feature that works
for all other 1023 IDs because 1 ID is quirky. Sounds like overkill
to me.

-- 
balbi