From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: ata, pcmcia: problem with irq and ata_dev_read_id() Date: Mon, 05 Jul 2010 11:33:19 +0200 Message-ID: <4C31A6DF.9080109@gmail.com> References: <4C034FAE.9090605@denx.de> <4C044C8F.8050406@gmail.com> <4C2833B2.3040209@denx.de> <4C2DFF43.6050502@gmail.com> <4C319741.3060602@denx.de> <4C319D31.60705@gmail.com> <4C31A519.7030806@denx.de> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-bw0-f46.google.com ([209.85.214.46]:49944 "EHLO mail-bw0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752732Ab0GEJd2 (ORCPT ); Mon, 5 Jul 2010 05:33:28 -0400 Received: by bwz1 with SMTP id 1so2588758bwz.19 for ; Mon, 05 Jul 2010 02:33:22 -0700 (PDT) In-Reply-To: <4C31A519.7030806@denx.de> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: hs@denx.de Cc: Robert Hancock , Jeff Garzik , linux-ide@vger.kernel.org Hello, On 07/05/2010 11:25 AM, Heiko Schocher wrote: >> Yeah, that's the new polling code kicking in. If the IRQ problem >> doesn't persiste (which should be the case here), polling will step >> down after a while and everything will return to normal. If you keep >> the system running more than ten minutes and use the CF device, does >> the kernel complain anymore? > > No, I can use the CF while kernel is in polling mode, also if the > kernel switched back to irq mode: > > Log, direct after kernel is up: > .. > 25: 9 MPC8XX SIU Level pata_pcmcia > 26: 10000 MPC8XX SIU Level pata_pcmcia ... > > No irq is used. > > -bash-3.2# dmesg > [...] > Freeing unused kernel memory: 132k init > IRQ 26: spurious polling finished, reenabling IRQ > -bash-3.2# > > Now it is back in irq mode: > > -bash-3.2# cat /proc/uptime > 419.65 370.56 > -bash-3.2# > ... > 25: 9 MPC8XX SIU Level pata_pcmcia > 26: 10033 MPC8XX SIU Level pata_pcmcia Cool, so it works as expected. With the new lost/spurious IRQ handling in place, removing TFLAG_POLLING from read_id for all controllers shouldn't cause much problem. However, the CF device is a pretty rare corner case and spurious IRQ handling can deal with it without too much problem, so leaving things as it is is probably better. Thanks for testing. -- tejun