From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:52864 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751280AbdGMMYN (ORCPT ); Thu, 13 Jul 2017 08:24:13 -0400 Date: Thu, 13 Jul 2017 14:24:03 +0200 From: Greg Kroah-Hartman To: Fabio Estevam Cc: stable@vger.kernel.org, peter.senna@collabora.com, s.hauer@pengutronix.de Subject: Re: imx-serial: RX DMA startup latency Message-ID: <20170713122403.GB18527@kroah.com> References: <1499897106-8147-1-git-send-email-festevam@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1499897106-8147-1-git-send-email-festevam@gmail.com> Sender: stable-owner@vger.kernel.org List-ID: On Wed, Jul 12, 2017 at 07:05:06PM -0300, Fabio Estevam wrote: > From: Peter Senna Tschudin > > commit 4dec2f119e86f9c91e60cdd8f0cc057452e331a9 upstream. > > 18a4208 introduced a change to reduce the RX DMA latency on the first reception > when the serial port was opened for reading. However it was claiming a hardirq > unsafe lock after a hardirq safe lock which is not allowed and causes lockdep > to complain verbosely. > > This patch changes the code to always start RX DMA earlier, instead of > relying on the flags used to open the serial port removing the code that > was looking for the serial file flags. > > Cc: #4.12.x > Signed-off-by: Peter Senna Tschudin > Tested-by: Sascha Hauer > Signed-off-by: Greg Kroah-Hartman > Signed-off-by: Fabio Estevam > --- > drivers/tty/serial/imx.c | 26 +++++--------------------- > 1 file changed, 5 insertions(+), 21 deletions(-) What are you asking for here, for this to be added to the 4.12-stable tree? Or something else? Please always be explicit... thanks, greg k-h