From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from imap.sh.mvista.com (unknown [63.81.120.155]) by ozlabs.org (Postfix) with ESMTP id 51FEF67BE8 for ; Mon, 20 Nov 2006 07:09:29 +1100 (EST) Message-ID: <4560BA57.40600@ru.mvista.com> Date: Sun, 19 Nov 2006 23:11:03 +0300 From: Sergei Shtylyov MIME-Version: 1.0 To: Benjamin Herrenschmidt Subject: Re: [PATCH] 2.6.18-rt7: PowerPC: fix breakage in threaded fasteoi type IRQ handlers References: <200611192243.34850.sshtylyov@ru.mvista.com> <1163966437.5826.99.camel@localhost.localdomain> <1163966649.5826.101.camel@localhost.localdomain> In-Reply-To: <1163966649.5826.101.camel@localhost.localdomain> Content-Type: text/plain; charset=us-ascii; format=flowed Cc: linuxppc-dev@ozlabs.org, mingo@elte.hu, linux-kernel@vger.kernel.org, dwalker@mvista.com List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Hello. Benjamin Herrenschmidt wrote: >>>As fasteoi type chips never had to define their ack() method before the >>>recent Ingo's change to handle_fasteoi_irq(), any attempt to execute handler >>>in thread resulted in the kernel crash. So, define their ack() methods to be >>>the same as their eoi() ones... >>>Signed-off-by: Sergei Shtylyov >>>--- >>>Since there was no feedback on three solutions I suggested, I'm going the way >>>of least resistance and making the fasteoi type chips behave the way that >>>handle_fasteoi_irq() is expecting from them... >>Wait wait wait .... Can somebody (Ingo ?) explain me why the fasteoi >>handler is being changed and what is the rationale for adding an ack >>that was not necessary before ? It's changed in the RT patch for the case of threaded IRQ. This patch is not for the mainline kernels. > To be more precise, I don't see in what circumstances a fasteoi type PIC > would need an ack routine that does something different than the eoi... > and if it always does the same thing, why not just call eoi ? Because Ingo decided that calling mask() and ack() methods was a better than calling mask() and eoi(). Here's the thread: http://ozlabs.org/pipermail/linuxppc-dev/2006-October/026546.html > Ben. WBR, Sergei