From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S268449AbUHYDrC (ORCPT ); Tue, 24 Aug 2004 23:47:02 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S268470AbUHYDrC (ORCPT ); Tue, 24 Aug 2004 23:47:02 -0400 Received: from fw.osdl.org ([65.172.181.6]:15051 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S268449AbUHYDqz (ORCPT ); Tue, 24 Aug 2004 23:46:55 -0400 Date: Tue, 24 Aug 2004 20:45:08 -0700 From: Andrew Morton To: Takashi Iwai Cc: linux-kernel@vger.kernel.org, thomas@undata.org Subject: Re: [PATCH] Fix shared interrupt handling of SA_INTERRUPT and SA_SAMPLE_RANDOM Message-Id: <20040824204508.3b31449f.akpm@osdl.org> In-Reply-To: References: X-Mailer: Sylpheed version 0.9.7 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Takashi Iwai wrote: > > while the recent investation of latency issues, Thomas Charbonne > suggested that there is a long-standing bug in the irq handler. > When the irq is shared, SA_INTERRUPT flag is checked only for the > first registered handler. When it's without SA_INTERRUPT, always > local_irq_enable() is called even if the second or later handler has > SA_INTERRUPT. That's because SA_INTERRUPT interrupts shouldn't be shared. The grey cell which remembered why this is so seems to have died, but I've put the email thread here: http://www.zip.com.au/~akpm/linux/patches/stuff/x.txt