Hello,
On Tue, 13 Sep 2011, Joshua Kinard wrote:
Date: Tue, 13 Sep 2011 08:43:39 -0400
From: Joshua Kinard <kumba@xxxxxxxxxx>
To: post@xxxxxxxx
Cc: linux-mips@xxxxxxxxxxxxxx, ralf@xxxxxxxxxxxxxx,
attilio.fiandrotti@xxxxxxxxx
Subject: Re: [PATCH] Impact video driver for SGI Indigo2
On 09/11/2011 07:14, peter fuerst wrote:
+#ifndef CONFIG_EARLY_PRINTK
+ if (ctype && strstr(ctype, "impact=early"))
+#endif
+ setup_impact_earlycons();
I think we can gut all the Impact early printk stuff. Per Skylark, to use
it, you have to drop a function call into arch/mips/kernel/setup.c and
kernel/printk.c,
It's the setup_impact_earlycons() call in ip22-setup.c above. In so far the
patch is complete, one can leave setup.c and printk.c alone.
Depending on the situation, ip22-setup.c may not be early enough. The
setup_impact_earlycons-call could be moved near to the beginning of
start_kernel() (init/main.c), it doesn't depend on non-static kernel setup.
But this had to be done by hand, it won't be in the regular source.
So, given the intended purpose of the early console - providing helpfull
information simply by a boot option to a potential bug report by an user,
who has no inclination to kernel hacking, just wants to use the kernel out
of the box - early console may or may not be usefull.
so I don't think this is an easily-used feature. In my
patchset for Gentoo's mips-sources, I actually broke both Impact and
Odyssey's early console bits out as separate drivers applied as patches if
one forces a debug mode on.
Do you intend to submit these drivers? Anyway i will separate the early
console stuff from the "basic" Impact-patch, when i resubmit the patches,
so it's optional and can be discussed independently.
Because they're not really even real
consoles....just a way to get output out of offbeat systems like Octane,
which hides all the good stuff behind the broken (horifically broken) IOC3
metadevice.
Unless you've come up with a better way to do early printk that can work
shortly after the CPUs are brought up?
No regular/every-day usable method, only debug-hackery:
Moving the setup_impact_earlycons-call to start_kernel() or using a specially
tailored ARCS-console, which in addition allows to capture kernel output via
serial line (and helped me debugging for long).
(BTW: in recent kernels any ARCS-console must be switched off very early,
while in e.g. 2.6.14 it could be used until Impact or IP22Zilog take over)
...
--
Joshua Kinard
Gentoo/MIPS
kumba@xxxxxxxxxx
4096R/D25D95E3 2011-03-28
"The past tempts us, the present confuses us, the future frightens us. And
our lives slip away, moment by moment, lost in that vast, terrible in-between."
--Emperor Turhan, Centauri Republic
kind regards
peter
