From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754706Ab2D1SJc (ORCPT ); Sat, 28 Apr 2012 14:09:32 -0400 Received: from mail-iy0-f174.google.com ([209.85.210.174]:53685 "EHLO mail-iy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751637Ab2D1SJa (ORCPT ); Sat, 28 Apr 2012 14:09:30 -0400 Message-ID: <4F9C3252.7020508@lwfinger.net> Date: Sat, 28 Apr 2012 13:09:22 -0500 From: Larry Finger User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:11.0) Gecko/20120328 Thunderbird/11.0.1 MIME-Version: 1.0 To: Benjamin Herrenschmidt CC: Paul Mackerras , linuxppc-dev@lists.ozlabs.org, LKML Subject: Re: Regression in 32-bit ppc kernel References: <4F973026.3020103@lwfinger.net> <1335311621.15830.42.camel@pasglop> <4F976352.4060001@lwfinger.net> <1335327081.21961.28.camel@pasglop> <4F98117C.7080309@lwfinger.net> <1335390257.21961.53.camel@pasglop> <4F9ABD67.3060704@lwfinger.net> <1335565573.20866.7.camel@pasglop> <4F9B3398.9060701@lwfinger.net> <1335573757.20866.12.camel@pasglop> In-Reply-To: <1335573757.20866.12.camel@pasglop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 04/27/2012 07:42 PM, Benjamin Herrenschmidt wrote: > > Ok, so you do have a serial port, probably two even :-) One of them is > connected to the infra red transceiver and the other one is probably > connected to the internal modem. > > (The modem itself might not use it, some of these machines use an > i2s/i2c modem, some use a usb modem, but the serial port is wired to the > connector regardless). I have done a little more debugging. The problem is definitely coming from drivers/tty/serial/pmac_zilog.c. I am getting ChanB interrupts while open, which causes the following code segment to return IRQ_NONE: if (r3 & (CHBEXT | CHBTxIP | CHBRxIP)) { if (!ZS_IS_OPEN(uap_a)) { pmz_debug("ChanB interrupt while open !\n"); goto skip_b; } write_zsreg(uap_b, R0, RES_H_IUS); zssync(uap_b); if (r3 & CHBEXT) When this section is entered, r3 == 0x2 (CHBTxIP). Larry