From mboxrd@z Thu Jan 1 00:00:00 1970 From: gyang Subject: Re: [PATCH 2/6] Blackfin Serial Driver: Add a debug function to serial driver. Date: Wed, 15 Oct 2008 10:23:41 +0800 Message-ID: <1224037421.6284.40.camel@dyang> References: <1223891185-13924-1-git-send-email-cooloney@kernel.org> <1223891185-13924-3-git-send-email-cooloney@kernel.org> <20081014142701.72090868@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=gbk Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from nwd2mail11.analog.com ([137.71.25.57]:16902 "EHLO nwd2mail11.analog.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751034AbYJOC1g convert rfc822-to-8bit (ORCPT ); Tue, 14 Oct 2008 22:27:36 -0400 In-Reply-To: <20081014142701.72090868@lxorguk.ukuu.org.uk> Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Alan Cox Cc: Bryan Wu , alan@redhat.com, linux-kernel@vger.kernel.org, linux-serial@vger.kernel.org Hi, Alan, We are making a SMP like patch to blackfin, cpu_relax() is replaced by = a data cache flush function which will count it to a per-cpu counter. If this serial function is called too early, the per-cpu data area have not been initialized, this call will cause crash. So we'd like to use barrier() instead of cpu_relax(). BRs, Graf =D4=DA 2008-10-14=B6=FE=B5=C4 14:27 +0100=A3=ACAlan Cox=D0=B4=B5=C0=A3=BA > > - cpu_relax(); > > + barrier(); > > + >=20 > Seems to be an odd unrelated change ? -- To unsubscribe from this list: send the line "unsubscribe linux-serial"= in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html