Re: ARC fails to boot on linux-next of 20140711

From: Rob Herring
Date: Fri Jul 25 2014 - 10:15:51 EST

On Fri, Jul 25, 2014 at 6:02 AM, Vineet Gupta
<Vineet.Gupta1@xxxxxxxxxxxx> wrote:
> Hi Grant,
> linux-next has a series for arc_uart (via tty tree) which converts it to generic
> earlycon and specifies console via /chosen/stdout-path vs. an explicit param in
> /chose/bootargs
> 2014-06-24 9da433c0a0b5 ARC: [arcfpga] stdout-path now suffices for earlycon/console
> This relied on prev commit of yours (from linux next of 20140711), which seem to
> have disappeared now.
> 2014-03-27 a9296cf2d0b6 of: Create of_console_check() for selecting a console
> specified in /chosen
> 2014-03-27 cfa9cacc5dd3 of: Enable console on serial ports specified by
> /chosen/stdout-path
> Is there a specific reason for dropping these patches (or perhaps a merge to be
> merged). I cherry-picked both but still doesn't work.
> Can you please advise next step forward, before I go off debugging with those
> patches in.

There's an issue that if you have stdout-path and "earlycon" on the
command line, the kernel will switch to tty0 and disable the earlycon.

This is the "fix", but I don't like adding the DT dependency into generic code:

@@ -2382,7 +2386,7 @@ void register_console(struct console *newcon)
if (newcon->setup == NULL ||
newcon->setup(newcon, NULL) == 0) {
newcon->flags |= CON_ENABLED;
- if (newcon->device) {
+ if (newcon->device && !of_stdout) {
newcon->flags |= CON_CONSDEV;
preferred_console = 0;

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