From mboxrd@z Thu Jan 1 00:00:00 1970 From: Joachim Buermann Subject: Fw: Delivery unsuccesful: Delivery problems Date: Tue, 18 Feb 2003 12:06:32 +0100 Sender: linux-serial-owner@vger.kernel.org Message-ID: <20030218120632.3ac769bb.jbuermann@zes.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Return-path: Received: from inv1253.zes.com (217.0.55.175) by websrvnt02 with MERCUR-SMTP/POP3/IMAP4-Server (v3.10.18 AS-0098309) for ; Tue, 18 Feb 2003 12:11:18 +0100 Received: from inv1253.zes.com (localhost [127.0.0.1]) by inv1253.zes.com (Postfix) with ESMTP id CE2E61F3B1 for ; Tue, 18 Feb 2003 12:06:33 +0100 (CET) Received: from inv1428.zes.com (inv1428.zes.com [192.168.2.28]) by inv1253.zes.com (Postfix) with SMTP id 306341F3A8 for ; Tue, 18 Feb 2003 12:06:33 +0100 (CET) List-Id: linux-serial@vger.kernel.org To: linux-serial@vger.kernel.org Hallo 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. Unfortunatelly 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 behaviour, 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. Additional to this I tried a PCI card with a 16950 (128 Byte fifo!) and set the uart with the setserial command. But also here a lot of overruns!!! >>From a embedded linux project (ELAN SC520 133MHz, kernel 2.2.19) I know, that the harddisk type influence the serial communication. So I got overruns after I changed the original drive with a newer one (the first was a old IBM with 500MByte, the newer a IBM with 20GByte). Last not least I must replace the linux kernel with a realtime linux (rtlinux) and do the serial communication in a realtime handler. Because I didn't want to replace my desktop machine with a realtime linux, I'm looking for some hints to solve this problems. What's about irqtune? I'm know this tool only with kernels up to 2.2.x. Is there a bug in the serial driver (I didn't found any hints in the mailing list or with google)? Should I change the PCI interrupts in the BIOS to set the interrupt priority? I don't know anymore. Please help. Many thanks in advance and sorry for my bad english Joachim