From mboxrd@z Thu Jan 1 00:00:00 1970 From: Toan Pham Subject: 8250 wrong IRQs set after boot Date: Wed, 24 Mar 2010 11:38:18 -0400 Message-ID: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: Received: from qw-out-2122.google.com ([74.125.92.27]:12480 "EHLO qw-out-2122.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756428Ab0CXPiT (ORCPT ); Wed, 24 Mar 2010 11:38:19 -0400 Received: by qw-out-2122.google.com with SMTP id 8so1911545qwh.37 for ; Wed, 24 Mar 2010 08:38:18 -0700 (PDT) Sender: linux-serial-owner@vger.kernel.org List-Id: linux-serial@vger.kernel.org To: linux-serial@vger.kernel.org Hi, I built a linux from scrach distro and setserial is not installed. At boot up; all of the IRQ numbers for serial ports 1-4 are reported correctly (according to the bios setting) from the bootup log. They are as followed. ttyS0 at 0x03f8 (irq = 4) is a 16550A ttyS1 at 0x02f8 (irq = 4) is a 16550A ttyS2 at 0x03e8 (irq = 11) is a 16550A ttyS3 at 0x02e8 (irq = 11) is a 16550A However, after bootup, i login and looked at /proc/tty/driver/serial, i noticed that all the IRQ for four serial ports are wrong, and they as as follow: ttyS0 to IRQ 4 ttyS1 to IRQ 3 ttyS2 to IRQ 4 ttyS3 to IRQ 3 as expected, serial ports ttyS1, ttyS2, and ttyS3 did not function because the IRQs were reconfigured somehow. I would like to know what reconfigured the IRQs since setserial is not installed in my distro. I also checked all the startup scripts in userspace and noticed that nothing would have reconfigured these ports. I am thinking about installing setserial to my distro to reconfigure the irqs back to the ones listed at bootup; however, I would like to know what caused them to change in the first place. Thank you, Toan