On 17.12.2009, at 19:46, Christoffer Dall wrote: > On Thu, Dec 17, 2009 at 1:20 PM, Hollis Blanchard <hollis at penguinppc.org> wrote: >> On Thu, Dec 17, 2009 at 12:24 AM, Christoffer Dall <cd2436 at columbia.edu> wrote: >>>> I don't understand why you don't have console. If you did, you could >>>> use the initcall_debug kernel parameter. >>> >>> The uart serial drivers on ARM rely on the tty, bus and driver >>> subsystems to be initialized, so this can't happen before the >>> initcalls. However, I got a response from the arm linux mailing list >>> about a recently committed fix for this, which I might try to apply. >> >> Surely there is an "early console" option for ARM, usable for >> debugging before all those driver layers have been initialized...? > > Usually yes, just not for the pl011 device that QEMU happens to > emulate - To my knowledge there's early support for an 8250 serial > device and a framebuffer based console, but I would have to change the > board configuration in QEMU and the guest kernel to map these things > up, and the framebuffer emualation on QEMU doesn't work easily on SDL > with Android. On S390 we just use a self-defined hypercall to send single characters. Invalid instructions that don't get handled in kernel-space just get forwarded to the userspace on S390. Alex
