From mboxrd@z Thu Jan 1 00:00:00 1970 From: Greg KH Subject: Re: [uclinux-dist-devel] [PATCH] serial: bfin_5xx: split uart RX lock from uart port lock to avoid deadlock Date: Thu, 3 Feb 2011 10:32:42 -0800 Message-ID: <20110203183242.GA20886@kroah.com> References: <1294723003-8496-1-git-send-email-vapier@gentoo.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Received: from kroah.org ([198.145.64.141]:53285 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932312Ab1BCScp (ORCPT ); Thu, 3 Feb 2011 13:32:45 -0500 Content-Disposition: inline In-Reply-To: Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: Mike Frysinger Cc: linux-serial@vger.kernel.org, Greg Kroah-Hartman , Alan Cox , uclinux-dist-devel@blackfin.uclinux.org On Thu, Feb 03, 2011 at 01:29:08AM -0500, Mike Frysinger wrote: > On Tue, Jan 11, 2011 at 00:16, Mike Frysinger wrote: > > From: Sonic Zhang > > > > The RX lock is used to protect the RX buffer from concurrent access= in DMA > > mode between the timer and RX interrupt routines. =A0It is independ= ent from > > the uart lock which is used to protect the TX buffer. =A0It is poss= ible for > > a uart TX transfer to be started up from the RX interrupt handler i= f low > > latency is enabled. =A0So we need to split the locks to avoid deadl= ocking in > > this situation. > > > > In PIO mode, the RX lock is not necessary because the handle_simple= _irq > > and handle_level_irq functions ensure driver interrupt handlers are= called > > once on one core. > > > > And now that the RX path has its own lock, the TX interrupt has not= hing to > > do with the RX path, so disabling it at the same time. >=20 > ping ... Is this needed for .38? thanks, greg k-h -- 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