From mboxrd@z Thu Jan 1 00:00:00 1970 From: nicolas.pitre@linaro.org (Nicolas Pitre) Date: Thu, 5 Apr 2012 20:19:57 -0400 (EDT) Subject: CONFIG_EARLY_PRINTK on versatile broken in mainline In-Reply-To: References: Message-ID: To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Thu, 5 Apr 2012, Grant Likely wrote: > On Thu, Apr 5, 2012 at 4:27 PM, Grant Likely wrote: > > On Thu, Apr 5, 2012 at 4:19 PM, Grant Likely wrote: > >> On Thu, Apr 5, 2012 at 4:08 PM, Fabio Estevam wrote: > >>> On Thu, Apr 5, 2012 at 7:52 PM, Grant Likely wrote: > >>>> Has anyone else had problems with CONFIG_EARLY_PRINTK on current > >>>> mainline? ?ARM versatile fails to boot on qemu when it is selected. > >>>> I've just started bisecting. ?v3.3 is okay, but current mainline is > >>>> broken. ?Output stops after dumping out the memblock regions, and > >>>> __log_buf stops at the same place. > >>> > >>> Please try this patch: > >>> http://permalink.gmane.org/gmane.linux.ports.arm.kernel/158694 > >> > >> I've already had that fix applied. ?This is a different issue. ?The > >> kernel boots fine if CONFIG_EARLY_PRINTK isn't defined. > > > > Update: I'm still investigating, but it bisects out to this commit: > > > > commit 94e5a85b3be0ce109d26aa6812b2a02c518a0e4b > > Author: Russell King > > Date: ? Wed Jan 18 15:32:49 2012 +0000 > > > > ? ?ARM: earlier initialization of vectors page > > The following patch makes it boot. Calling printch() to output a > character right after early_trap_init() seems to unblock whatever was > wedging the system. A delay or a printk with "" format string doesn't > have any effect, it seems it must be a character output. This may be > a problem in the simulator. I've not been able to run this on real > hardware. FWIW, I have no problem booting v3.4-rc1 for vexpress on the ARM A15 Fast Model, given the patch referenced above is applied. Nicolas