From owner-freebsd-net@FreeBSD.ORG Wed Aug 23 23:56:51 2006 Return-Path: X-Original-To: net@FreeBSD.org Delivered-To: freebsd-net@FreeBSD.ORG Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 3E40B16A4E2; Wed, 23 Aug 2006 23:56:51 +0000 (UTC) (envelope-from oleg@lath.rinet.ru) Received: from lath.rinet.ru (lath.rinet.ru [195.54.192.90]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4A0D243D8A; Wed, 23 Aug 2006 23:56:42 +0000 (GMT) (envelope-from oleg@lath.rinet.ru) Received: from lath.rinet.ru (localhost [127.0.0.1]) by lath.rinet.ru (8.13.6/8.13.6) with ESMTP id k7NNuXf3027269 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Thu, 24 Aug 2006 03:56:33 +0400 (MSD) (envelope-from oleg@lath.rinet.ru) Received: (from oleg@localhost) by lath.rinet.ru (8.13.6/8.13.6/Submit) id k7NNuWOS027268; Thu, 24 Aug 2006 03:56:32 +0400 (MSD) (envelope-from oleg) Date: Thu, 24 Aug 2006 03:56:32 +0400 From: Oleg Bulyzhin To: David Christensen Message-ID: <20060823235632.GA25876@lath.rinet.ru> References: <20060823161649.GE76666@cell.sick.ru> <09BFF2FA5EAB4A45B6655E151BBDD90301D43002@NT-IRVA-0750.brcm.ad.broadcom.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <09BFF2FA5EAB4A45B6655E151BBDD90301D43002@NT-IRVA-0750.brcm.ad.broadcom.com> User-Agent: Mutt/1.5.11 Cc: brad@openbsd.org, Gleb Smirnoff , net@FreeBSD.org Subject: Re: bge(4) one packet wedge X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 23 Aug 2006 23:56:51 -0000 On Wed, Aug 23, 2006 at 12:53:49PM -0700, David Christensen wrote: > This "lost interrupt" type of problem is addressed by the use of the > status_tag > field in the status block. (Listed as bge_rsvd0 in the bge_status_block > structure). > Everytime the status block is updated a new tag value is written to the > status block. > When the ISR starts the driver should record the status_tag value. At > the end > of the ISR, the driver should compare the current status_tag value is > the status > block with the value recorded on entry to the ISR. If the values are > the same > then no additional status block updates have occurred so there shouldn't > be > any packets hanging around. If the values are different then additional > packets > or completions are waiting around so the ISR should loop around again. > At the > end of the ISR the driver will write the status_tag value it last > handled to a > mailbox register, letting the hardware know the last status block update > handled. > If necessary the hardware will generate a new interrupt and start the > process over > again. > > This entire process should be included in the Linux driver, I don't see > it being > used in the bge driver (bge_intr()). > > Dave > Could you please answer few questions? 1) I've found status tag is returned in status block even if bit 9 of Misc. Host Control Register is not set, is it ok? 2) Status tag is returned in bits 0-7 of status tag field of status block, as long as i know it should be returned in bits 31-24, is it ok? 3) If i try to return processed tag (at the end of ISR) in Mailbox 0 register: CSR_WRITE_4(sc, BGE_MBX_IRQ0_LO, status_tag << 24); it would lead to disabled interrupts. I've thought this should not happen cause in_isr bits (0-23) are cleared. -- Oleg.