From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Walker Subject: i2c device hangs the whole bus, recovery ? Date: Thu, 14 Apr 2016 16:34:29 -0700 Message-ID: <57102905.7080904@cisco.com> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from alln-iport-1.cisco.com ([173.37.142.88]:56636 "EHLO alln-iport-1.cisco.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751867AbcDNXoK (ORCPT ); Thu, 14 Apr 2016 19:44:10 -0400 Sender: linux-i2c-owner@vger.kernel.org List-Id: linux-i2c@vger.kernel.org To: linux-i2c@vger.kernel.org, "xe-kernel@external.cisco.com" , "Anil Veliyankara Madam (aveliyan)" , "Perry Li (chuangli)" Hi all, We have a pca954x MUX and connected to this is some devices. We have one device connected to the MUX which goes bad, and when we try to communicate with the bad device (we don't know it's bad yet) , it causes one of the i2c lines to go low and makes it impossible to connect with any of the other devices on the bus. I don't know how common this type of situation is, but I thought I would ask here how people would recover from this condition ? Is there a standard way to do it, or is the standard way to reboot the machine ? I think ideally I would like to be able to detect that something is wrong, and black list the device, and recover if possible. Any suggestions appreciated, Daniel