From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751831AbaHTGkh (ORCPT ); Wed, 20 Aug 2014 02:40:37 -0400 Received: from filter1.ibarracuda.nl ([83.247.7.10]:54397 "EHLO filter1.ibarracuda.nl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750942AbaHTGke (ORCPT ); Wed, 20 Aug 2014 02:40:34 -0400 X-ASG-Debug-ID: 1408516830-0759e7416b4aa4ac0002-xx1T2L X-Barracuda-Envelope-From: Frans.Klaver@xsens.com X-Barracuda-AUTH-User: xsenscom X-Barracuda-Apparent-Source-IP: 87.249.116.215 Date: Wed, 20 Aug 2014 08:40:28 +0200 From: Frans Klaver To: Felipe Balbi CC: Tony Lindgren , Rob Herring , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , Greg Kroah-Hartman , Alexey Pelykh , Jiri Slaby , Frans Klaver , , , , , Subject: Re: [RFC PATCH 3/4] tty: omap-serial: use threaded interrupt handler Message-ID: <20140820064028.GC9319@ci00147.xsens-tech.local> X-ASG-Orig-Subj: Re: [RFC PATCH 3/4] tty: omap-serial: use threaded interrupt handler References: <1406645577-18620-1-git-send-email-frans.klaver@xsens.com> <1408450488-4083-1-git-send-email-frans.klaver@xsens.com> <1408450488-4083-4-git-send-email-frans.klaver@xsens.com> <20140819185701.GC22003@saruman.home> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline In-Reply-To: <20140819185701.GC22003@saruman.home> User-Agent: Mutt/1.5.23 (2014-03-12) X-Originating-IP: [172.16.11.49] X-Barracuda-Connect: rev-215.116.249.87.virtu.nl[87.249.116.215] X-Barracuda-Start-Time: 1408516830 X-Barracuda-Encrypted: AES128-SHA X-Barracuda-URL: http://filter1.ibarracuda.nl:8000/cgi-mod/mark.cgi X-Barracuda-BRTS-Status: 1 X-Barracuda-Spam-Score: 0.00 X-Barracuda-Spam-Status: No, SCORE=0.00 using per-user scores of TAG_LEVEL=1000.0 QUARANTINE_LEVEL=1000.0 KILL_LEVEL=5.0 tests= X-Barracuda-Spam-Report: Code version 3.2, rules version 3.2.3.8641 Rule breakdown below pts rule name description ---- ---------------------- -------------------------------------------------- Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 19, 2014 at 01:57:02PM -0500, Felipe Balbi wrote: > On Tue, Aug 19, 2014 at 02:14:47PM +0200, Frans Klaver wrote: > > At 3.6Mbaud, with slightly over 2Mbit/s data coming in, we see 1600 uart > > rx buffer overflows within 30 seconds. Threading the interrupt handling reduces > > this to about 170 overflows in 10 minutes. > > Can you try Sebastian Siewior's patches for 8250_omap and 8250 dma > support ? That should help you a lot. I'll have a look at that series. Thanks for pointing it out. > > drivers/tty/serial/omap-serial.c | 31 ++++++++++++++++++++++++------- > > 1 file changed, 24 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c > > index 14a0167..57664b9 100644 > > --- a/drivers/tty/serial/omap-serial.c > > +++ b/drivers/tty/serial/omap-serial.c > > @@ -575,6 +575,21 @@ static void serial_omap_rdi(struct uart_omap_port *up, unsigned int lsr) > > } > > > > /** > > + * serial_omap_fast_irq() - schedule interrupt handling > > + */ > > +static irqreturn_t serial_omap_fast_irq(int irq, void *dev_id) > > +{ > > + struct uart_omap_port *up = dev_id; > > + unsigned int iir = serial_in(up, UART_IIR); > > + > > + if (iir & UART_IIR_NO_INT) > > + return IRQ_NONE; > > + > > + disable_irq_nosync(up->port.irq); > > NAK. Either use IRQF_ONESHOT or actually mask the IRQs at the device's > registers (basically clearing IER). Given the work that's been done on the 8250 based driver, what are the short-term chances omap-serial will be dropped? I'd be happy to improve here if it makes sense to do so. If the 8250 based driver is going to replace omap-serial anyway on the short term, I don't see the point of further developing this patch. The others would still make sense in my opinion. Thanks, Frans