lkml.org 
[lkml]   [2016]   [Dec]   [2]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATH net v2] cdc_ether: Fix handling connection notification
From
From: Kristian Evensen <kristian.evensen@gmail.com>
Date: Thu, 1 Dec 2016 14:23:17 +0100

> Commit bfe9b9d2df66 ("cdc_ether: Improve ZTE MF823/831/910 handling")
> introduced a work-around in usbnet_cdc_status() for devices that exported
> cdc carrier on twice on connect. Before the commit, this behavior caused
> the link state to be incorrect. It was assumed that all CDC Ethernet
> devices would either export this behavior, or send one off and then one on
> notification (which seems to be the default behavior).
>
> Unfortunately, it turns out multiple devices sends a connection
> notification multiple times per second (via an interrupt), even when
> connection state does not change. This has been observed with several
> different USB LAN dongles (at least), for example 13b1:0041 (Linksys).
> After bfe9b9d2df66, the link state has been set as down and then up for
> each notification. This has caused a flood of Netlink NEWLINK messages and
> syslog to be flooded with messages similar to:
>
> cdc_ether 2-1:2.0 eth1: kevent 12 may have been dropped
>
> This commit fixes the behavior by reverting usbnet_cdc_status() to how it
> was before bfe9b9d2df66. The work-around has been moved to a separate
> status-function which is only called when a known, affect device is
> detected.
>
> v1->v2:
>
> * Do not open-code netif_carrier_ok() (thanks Henning Schild).
> * Call netif_carrier_off() instead of usb_link_change(). This prevents
> calling schedule_work() twice without giving the work queue a chance to be
> processed (thanks Bjørn Mork).
>
> Fixes: bfe9b9d2df66 ("cdc_ether: Improve ZTE MF823/831/910 handling")
> Reported-by: Henning Schild <henning.schild@siemens.com>
> Signed-off-by: Kristian Evensen <kristian.evensen@gmail.com>

Applied and queued up for -stable, thanks.

\
 
 \ /
  Last update: 2016-12-02 19:44    [W:0.035 / U:0.572 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site