From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Lawyer Subject: Re: overruns with kernel 2.4.19 Date: Tue, 18 Feb 2003 15:05:33 -0800 Sender: linux-serial-owner@vger.kernel.org Message-ID: <20030218230533.GB480@lafn.org> References: <20030218144346.3e056a65.jbuermann@zes.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from localhost (mail@host-66-81-29-63.rev.o1.com [66.81.29.63]) by zoon.lafn.org (8.12.3/8.11.3) with ESMTP id h1ING1nX043678 for ; Tue, 18 Feb 2003 15:16:01 -0800 (PST) (envelope-from dave@lafn.org) Received: from dave by localhost with local (Exim 3.36 #1 (Debian)) id 18lGnt-0000B5-00 for ; Tue, 18 Feb 2003 15:05:33 -0800 Content-Disposition: inline In-Reply-To: <20030218144346.3e056a65.jbuermann@zes.com> List-Id: linux-serial@vger.kernel.org To: linux-serial@vger.kernel.org On Tue, Feb 18, 2003 at 02:43:46PM +0100, Joachim Buermann wrote: > Hello all, > > I`m using linux mandrake kernel 2.4.19 on a 2 GHz Pentium 4 with 128 > MByte RAM. The serial port /dev/cua0 is connected to a external device > and receives data with 115200 Baud. The cua devices have been obsolete for some time. > > Unfortunately I get a lot of fifo overruns. I have unmasked the hda > interrupts with: > > hdparm -u1 /dev/hda > > also set the low_latency flag in the serial driver. The harddisk dma > couldn't disabled. > > I'm wonder at this behavior, because with a lower machine (Pentium I > 120 MHz, Kernel 2.2.13) I get overruns only once in a blue moon. And I > expected, that a 2 GHz machine should be quick enough, to responds to > the serial interrupts. Almost the same for me. On a Pentium I 90 MHz I get no overruns with kernel 2.2.20, but get hundreds of overruns on the same machine with kernel 2.4.19. Something is wrong with the software. > David Lawyer