Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761486Ab3JQAxb (ORCPT ); Wed, 16 Oct 2013 20:53:31 -0400 Received: from mail-ob0-f178.google.com ([209.85.214.178]:64912 "EHLO mail-ob0-f178.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760722Ab3JQAx3 (ORCPT ); Wed, 16 Oct 2013 20:53:29 -0400 MIME-Version: 1.0 In-Reply-To: <20131016235730.GK7082@xanatos> References: <1381872227-24757-1-git-send-email-jwerner@chromium.org> <525DB456.1040006@cogentembedded.com> <1381884300-403-1-git-send-email-jwerner@chromium.org> <20131016235730.GK7082@xanatos> Date: Wed, 16 Oct 2013 17:53:28 -0700 X-Google-Sender-Auth: CXR8UmyNVXeC5CkeVvriNxpd8Ac Message-ID: Subject: Re: [PATCH v2] usb: hub: Clear Port Reset Change during init/resume From: Julius Werner To: Sarah Sharp Cc: Julius Werner , Greg Kroah-Hartman , LKML , "linux-usb@vger.kernel.org" , Alan Stern , Benson Leung , Vincent Palatin , Duncan Laurie Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1201 Lines: 21 > Did you run into an issue where port status change events weren't being > generated because the Port Reset flag was set? I'm trying to figure out > if this addresses a real issue you hit (and thus should be queued for > stable), or if this is just a precaution. As Benson said, we're seeing this on the HP Chromebook 14 (Intel LynxPoint xHC). It only happens after system suspend/resume, so I'm not sure if there even is an xHC reset involved (not by the kernel anyway, but with all that other stuff it's hard to say). Note that we build our own firmware (including SMM/ACPI handlers), so this does not directly translate to LynxPoint PCs, but I think we based some of our code off Intel reference code and guides which may have already included the problem. I've found port reset code in both our firmware resume path and ACPI _PS0 handler, but they both seem to clear all Port Change bits correctly, so we are not sure about our true root cause yet. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/