From owner-freebsd-hackers Sat Nov 13 0:56:17 1999 Delivered-To: freebsd-hackers@freebsd.org Received: from dingo.cdrom.com (castles538.castles.com [208.214.165.102]) by hub.freebsd.org (Postfix) with ESMTP id E291B1501F; Sat, 13 Nov 1999 00:56:03 -0800 (PST) (envelope-from mike@dingo.cdrom.com) Received: from dingo.cdrom.com (localhost [127.0.0.1]) by dingo.cdrom.com (8.9.3/8.8.8) with ESMTP id AAA00574; Sat, 13 Nov 1999 00:46:56 -0800 (PST) (envelope-from mike@dingo.cdrom.com) Message-Id: <199911130846.AAA00574@dingo.cdrom.com> X-Mailer: exmh version 2.0.2 2/24/98 To: Brian McGovern Cc: hackers@freebsd.org, peter@freebsd.org Subject: Re: How does sio handle full clists? In-reply-to: Your message of "Tue, 09 Nov 1999 10:55:52 EST." <199911091555.KAA01889@bmcgover-pc.cisco.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Sat, 13 Nov 1999 00:46:56 -0800 From: Mike Smith Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > I've been digging around in the sio driver, trying to find out how it handles > receive interrupts when the clists are full. > > What I think I found (which is why I'm asking) is that if an RX interrupt > occurs, and the clists are full and the driver can't offload all of the > data from the UART, it disables the interrupts. I don't believe it does this, no. > I guess I'm looking for confirmation of this, and, if I'm way off, maybe a > quick explanatio of what _really_ happens. I'm looking at trying to reuse > the behavior elsewhere, so I want a good understanding of the process before I > get myself in to too much trouble. You should expect to see the dreaded "tty-level buffer overflow" message, when the soft interrupt handler flushes the interrupt-level buffers into the tty subsystem. -- \\ Give a man a fish, and you feed him for a day. \\ Mike Smith \\ Tell him he should learn how to fish himself, \\ msmith@freebsd.org \\ and he'll hate you for a lifetime. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message