From mboxrd@z Thu Jan 1 00:00:00 1970 From: yeasah@comrex.com (Yeasah Pell) Date: Wed, 02 Dec 2009 11:39:10 -0500 Subject: strange, spurious seeming vector exception on pxa300 In-Reply-To: <20091202160400.GE14091@buzzloop.caiaq.de> References: <4B159524.2020408@comrex.com> <4B167C69.6060903@comrex.com> <20091202155057.GA30669@n2100.arm.linux.org.uk> <20091202160400.GE14091@buzzloop.caiaq.de> Message-ID: <4B16982E.2000704@comrex.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Daniel Mack wrote: > On Wed, Dec 02, 2009 at 03:50:57PM +0000, Russell King - ARM Linux wrote: >> >> >> Given that the conditions are clearly wrong for a vector exception, I would >> say that you're hitting some kind of hardware bug - maybe caused by a dirty >> power supply to the PXA, causing it to misbehave? >> Of course I desperately want to believe this, as then I can ignore all this insanity and move on, but it's a bit difficult to swallow that some kind of hardware issue would cause a failure that is so consistent (same instruction every time, regardless of physical/virtual memory locations, compilation flags, etc.) yet caused absolutely no other perceptible problems... > We've had trouble of that kind as well some month ago with an early > prototype. It wasn't an exception we got, but the bug was clearly > hitting the same code path every single time, so this issue might be > related. Eventually it went away with new board revision which made wire > patching around the DDR SDRAM unnecessary (i.e, cleaner signal pathes). > > Strange enough, I would have expected such flaws to cause processor > misbeviour of all sorts, totally random and unpredictable. The fact that > is was the same function we always ended up in is still some kind of > miracle I can't explain. > > Daniel > ...and having some anecdotal evidence of that kind of situation happening is helpful. Thanks, guys.