From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by ozlabs.org (Postfix) with ESMTPS id 245D6DDFC4 for ; Sat, 5 Apr 2008 04:38:35 +1100 (EST) In-Reply-To: <20080404052955.GC11799@lixom.net> References: <20080403190943.GA16446@ru.mvista.com> <1207259436.10388.337.camel@pasglop> <20080404052955.GC11799@lixom.net> Mime-Version: 1.0 (Apple Message framework v623) Content-Type: text/plain; charset=US-ASCII; format=flowed Message-Id: <9d19fecb0ef172995b7ce3a317ee3c0d@kernel.crashing.org> From: Segher Boessenkool Subject: Re: [PATCH] PowerPC: MPIC ack interrupts at mpic_teardown_this_cpu() Date: Fri, 4 Apr 2008 19:38:27 +0200 To: Olof Johansson Cc: linuxppc-dev@ozlabs.org List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , >>> We really need to ack interrupts at mpic_teardown, since >>> not all platforms reset mpic at kernel start-up. For example, >>> kexec'ed kernel hangs on P.A. Semi if mpic_eoi() isn't called. >>> >>> Signed-off-by: Valentine Barshak >>> --- >> >> Would be interesting to find out why it hangs tho... it shouldn't . > > I haven't reproduced the problem and looked at hardware state yet, but > I > would expect it to be because the openpic won't send another interrupt > until the previous is EOI'd, and the IPI is never EOI'd as far as I > can tell. > > The XICS code does it explicitly already. I'm surprised it doesn't > break > on the 970-based platforms actually... platforms/maple/setup.c and platforms/powermac/pic.c use MPIC_WANTS_RESET. Is there a reason why we don't do that on every MPIC? If there is such a reason, the default should be to reset, only pseries and chrp and cell and now pasemi do not use it. It's the only sane way to get an MPIC into a sane known state starting from state. Segher