From owner-freebsd-bugs@FreeBSD.ORG Thu Dec 9 18:50:29 2004 Return-Path: Delivered-To: freebsd-bugs@hub.freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id F0DFF16A4CF for ; Thu, 9 Dec 2004 18:50:28 +0000 (GMT) Received: from freefall.freebsd.org (freefall.freebsd.org [216.136.204.21]) by mx1.FreeBSD.org (Postfix) with ESMTP id 782F543D46 for ; Thu, 9 Dec 2004 18:50:23 +0000 (GMT) (envelope-from gnats@FreeBSD.org) Received: from freefall.freebsd.org (gnats@localhost [127.0.0.1]) by freefall.freebsd.org (8.13.1/8.13.1) with ESMTP id iB9IoNQ2097925 for ; Thu, 9 Dec 2004 18:50:23 GMT (envelope-from gnats@freefall.freebsd.org) Received: (from gnats@localhost) by freefall.freebsd.org (8.13.1/8.13.1/Submit) id iB9IoNH3097924; Thu, 9 Dec 2004 18:50:23 GMT (envelope-from gnats) Date: Thu, 9 Dec 2004 18:50:23 GMT Message-Id: <200412091850.iB9IoNH3097924@freefall.freebsd.org> To: freebsd-bugs@FreeBSD.org From: Mike Tancsa Subject: Re: misc/74786: Smartlink Modem causes interrupt storm on RELENG_4 and RELENG_5 X-BeenThere: freebsd-bugs@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list Reply-To: Mike Tancsa List-Id: Bug reports List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 09 Dec 2004 18:50:29 -0000 The following reply was made to PR kern/74786; it has been noted by GNATS. From: Mike Tancsa To: Bruce Evans Cc: freebsd-gnats-submit@freebsd.org, freebsd-stable@freebsd.org Subject: Re: misc/74786: Smartlink Modem causes interrupt storm on RELENG_4 and RELENG_5 Date: Thu, 09 Dec 2004 13:43:32 -0500 [cc'ing to FreeBSD-Stable] Hi, I know that the proposed patches I submitted are not the best patches, but given that the next release of RELENG_4 is coming out, would it not be better to commit those to RELENG_4 as they allow the modem to work when it shares an interrupt with another device ? The sio and interrupt handling code in RELENG_5 is different enough that I doubt the patches you are proposing would make it back to RELENG_4. This at least lets the modem work and prevents the machine from locking up in an interrupt storm on RELENG_4 without breaking any functionality (as far as I know). ---Mike At 02:22 AM 08/12/2004, Bruce Evans wrote: >I think I understand this now. sio can indeed drive the interrupt (after >you open an sio device, but not immediately at the end of the attach >except in the serial console case). The main bugs are: >1. sio asks for exclusive access to the interrupt for no good reason > (some buses like isa might only support exclusive accesses, but sio > doesn't care). uhci gets access first in your configuration, so > allocation of the interrupt resource fails. >2. Error handling for the failure in (1) is null, so both devices are > "successfully" attached. >3. sio sets a flag to tell it to use polling if there is no interrupt > resource, but it doesn't set the flag if the interrupt resource > couldn't be allocated or if the interrupt couldn't be set up. >4. Upper layers provide negative help for debugging (3) using their > own version of (3). They print "irq N" in boot messages if an > interrupt resource justs exists. This doesn't mean that the device > is using it. >5. Device interrupts are still enabled in polling mode. This depends > on nothing else sucessfully setting up the (shared) interrupt.