From mboxrd@z Thu Jan 1 00:00:00 1970 From: tony@atomide.com (Tony Lindgren) Date: Fri, 16 Jan 2015 08:41:06 -0800 Subject: Regression with legacy IRQ numbers caused by 9a1091ef0017 In-Reply-To: <20150116163019.GW11502@n2100.arm.linux.org.uk> References: <20150114221407.GS2419@atomide.com> <20150115105035.GU11502@n2100.arm.linux.org.uk> <20150115152838.GB18552@atomide.com> <20150115171924.GV11502@n2100.arm.linux.org.uk> <20150116162119.GK18552@atomide.com> <20150116163019.GW11502@n2100.arm.linux.org.uk> Message-ID: <20150116164105.GL18552@atomide.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org * Russell King - ARM Linux [150116 08:33]: > On Fri, Jan 16, 2015 at 08:21:20AM -0800, Tony Lindgren wrote: > > * Russell King - ARM Linux [150115 09:22]: > > > On Thu, Jan 15, 2015 at 07:28:39AM -0800, Tony Lindgren wrote: > > > > * Russell King - ARM Linux [150115 02:53]: > > > > > I don't think we've proven a link there. While you're right that it > > > > > causes the wrong interrupt to be claimed, I have two kernels here, > > > > > both claim the same interrupt, one which is multi-platform and issues > > > > > that strange warning, and one which targets only OMAP4 which doesn't. > > > > > > > > > > There's something else going on which causes the bus errors which we > > > > > haven't found. > > > > > > > > I think it gets triggered if you enable PREEMPT. > > > > > > That's something which we can try to prove... build running now with > > > CONFIG_PREEMPT=y > > > > Looks like you now have the omap_l3_noc error appear for sdp4430 in > > your logs after enabling PREEMPT. > > > > I guess that means case closed for this one? > > I would still like to understand /why/ enabling preempt causes the error. > Changing the preempt configuration really should not change what happens > on the bus. (Think about it.) It's an indication that there is some > other error present. We have a wrong irq number caused by $subject. And the wrong irq gets triggered before the dma hardware is configured during dma init. And then we get the invalid access error from omap_l3_noc. > Unfortunately, the OMAP hardware appears to make it impossible to > determine what the access that caused the error was, so it looks like > it's pretty much undebuggable. Yeah would be nice to have more info from omap_l3_noc. Regards, Tony