From mboxrd@z Thu Jan 1 00:00:00 1970 From: daniel@caiaq.de (Daniel Mack) Date: Wed, 2 Dec 2009 17:04:00 +0100 Subject: strange, spurious seeming vector exception on pxa300 In-Reply-To: <20091202155057.GA30669@n2100.arm.linux.org.uk> References: <4B159524.2020408@comrex.com> <4B167C69.6060903@comrex.com> <20091202155057.GA30669@n2100.arm.linux.org.uk> Message-ID: <20091202160400.GE14091@buzzloop.caiaq.de> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Wed, Dec 02, 2009 at 03:50:57PM +0000, Russell King - ARM Linux wrote: > > r12 0x401d6c20 1075670048 > > sp 0x412c8a2c 0x412c8a2c > > lr 0x4029603c 1076453436 > > pc 0x400ec47c 0x400ec47c > > fps 0x0 0 > > cpsr 0x60000010 1610612752 > > CPSR says NZCV=0110 (zero, carry). 32-bit user mode. > > 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? 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