From mboxrd@z Thu Jan 1 00:00:00 1970 From: Oliver Hartkopp Subject: Re: [PATCH v3] can/sja1000: add support for PEAK-System PCMCIA card Date: Wed, 15 Feb 2012 20:46:06 +0100 Message-ID: <4F3C0B7E.1060806@hartkopp.net> References: <1328543779-9209-1-git-send-email-s.grosjean@peak-system.com> <4F38D46D.5010406@pengutronix.de> <4F38DF75.3040000@peak-system.com> <4F38E274.4050304@grandegger.com> <4F38E8DA.9060000@hartkopp.net> <4F38EDB1.7080209@grandegger.com> <4F38EEAD.3060607@pengutronix.de> <4F38EF3A.7040907@grandegger.com> <4F396AC9.8090308@hartkopp.net> <4F397145.8040007@grandegger.com> <4F3A307C.1050706@hartkopp.net> <4F3A3493.8010900@peak-system.com> <4F3A8ECB.7090803@hartkopp.net> <4F3B58D1.1040804@grandegger.com> <4F3B9C86.8030105@peak-system.com> <4F3BC9DB.6040604@grandegger.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mo-p00-ob.rzone.de ([81.169.146.161]:57466 "EHLO mo-p00-ob.rzone.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754987Ab2BOTqO (ORCPT ); Wed, 15 Feb 2012 14:46:14 -0500 In-Reply-To: <4F3BC9DB.6040604@grandegger.com> Sender: linux-can-owner@vger.kernel.org List-ID: To: Wolfgang Grandegger Cc: Stephane Grosjean , Marc Kleine-Budde , linux-can Mailing List >> I would also have say that before, but I checked that IRQ_NONE may be >> processed as spurious, so I don't even know, for the moment. LDD3 >> chapter 10 also says: >> >>> Interrupt handlers should return a value indicating whether there was >>> actually an >>> interrupt to handle. If the handler found that its device did, indeed, >>> need attention, it >>> should return IRQ_HANDLED; otherwise the return value should be IRQ_NONE. >> >> So, what does this "need attention" stands for? Since the device is >> unplugged, we could say that it didn't need any attention anymore... >> But, on the other hand, the ems_pcmcia driver does return IRQ_HANDLED >> when its private check fails to detect the card and it has been >> approved, so, where is the truth? Near the perfection? ;-) > > From http://lxr.linux.no/#linux+v3.2.6/include/linux/irqreturn.h: > > IRQ_NONE interrupt was not from this device See: http://lxr.linux.no/#linux+v3.2.6/kernel/irq/spurious.c#L178 I think at plug-out we get very little IRQ_NONE return values that should be ok not to damage the entire handling of that specific irq line ... Regards, Oliver