From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757586AbcJTJIm (ORCPT ); Thu, 20 Oct 2016 05:08:42 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:39016 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755840AbcJTJIj (ORCPT ); Thu, 20 Oct 2016 05:08:39 -0400 Date: Thu, 20 Oct 2016 11:08:36 +0200 From: Peter Zijlstra To: Lu Baolu Cc: Greg Kroah-Hartman , Mathias Nyman , Ingo Molnar , linux-usb@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RESEND PATCH v2 1/4] usb: dbc: early driver for xhci debug capability Message-ID: <20161020090836.GH3157@twins.programming.kicks-ass.net> References: <1476836305-4468-1-git-send-email-baolu.lu@linux.intel.com> <1476836305-4468-2-git-send-email-baolu.lu@linux.intel.com> <20161019130943.GA3175@twins.programming.kicks-ass.net> <58087B71.2040509@linux.intel.com> <20161020084132.GR3102@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161020084132.GR3102@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.23.1 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Oct 20, 2016 at 10:41:32AM +0200, Peter Zijlstra wrote: > I'm already only using early_printk() because regular printk() is an > unfixable piece of crap, and now you're making early_printk() useless > too. Note that the existing USB debug port stuff doesn't seem to have a single lock in. Its just polling on readl and doing writel without any serialization what so ever. Not that I've ever actually used it (lack of the magic cable), but it at least looks like it should mostly work.