| Message ID | 1378052656.25743.33.camel@deadeye.wl.decadent.org.uk (mailing list archive) |
|---|---|
| State | Not Applicable |
| Headers | show |
On Sun, 2013-09-01 at 17:24 +0100, Ben Hutchings wrote: > The original version of this was done by Bastian Blank, who wrote: > > > The problem is the following: > > - Architecture specific code sets preferred console to something bogus. > > - Command line handling tries to set preferred console but is overruled > > by the old setting. > > > > The udbg0 console is a boot console and independant. > > References: http://bugs.debian.org/492703 > Signed-off-by: Ben Hutchings <ben@decadent.org.uk> > --- > We've been carrying this in Debian for 5 years now, so it's about time > it got reviewed. > > I'm not convinced strstr() is the right way to check the command line > (what if there's also a 'netconsole='?). Also I think the problem should be solved elsewhere :-) In the end, what that code is trying to do (as are all the other similar instances) is to set "this is a good default in case nothing is specified *or* what is specified doesn't actually exist". Of course "doesn't exist" is tricky since the console could be provided by a module loaded god knows when ... but in that case, maybe it does make sense to stick to one of the known good defaults. After all, init will fail without a tty ... So I'm thinking we should in kernel/printk.c keep track of all those "arch defaults" when console= is specified as "latent" consoles, and right before starting init, if the specified one didn't work out (we have no console with an associated tty), then go through those latent ones and pick one that works. Cheers, Ben.
On Mon, Sep 02, 2013 at 09:55:40AM +1000, Benjamin Herrenschmidt wrote: > On Sun, 2013-09-01 at 17:24 +0100, Ben Hutchings wrote: > > The original version of this was done by Bastian Blank, who wrote: > > > > > The problem is the following: > > > - Architecture specific code sets preferred console to something bogus. > > > - Command line handling tries to set preferred console but is overruled > > > by the old setting. > > > > > > The udbg0 console is a boot console and independant. > > > > References: http://bugs.debian.org/492703 > > Signed-off-by: Ben Hutchings <ben@decadent.org.uk> > > --- > > We've been carrying this in Debian for 5 years now, so it's about time > > it got reviewed. > > > > I'm not convinced strstr() is the right way to check the command line > > (what if there's also a 'netconsole='?). > > Also I think the problem should be solved elsewhere :-) > > In the end, what that code is trying to do (as are all the other similar > instances) is to set "this is a good default in case nothing is > specified *or* what is specified doesn't actually exist". > > Of course "doesn't exist" is tricky since the console could be provided > by a module loaded god knows when ... but in that case, maybe it does > make sense to stick to one of the known good defaults. After all, init > will fail without a tty ... > > So I'm thinking we should in kernel/printk.c keep track of all those > "arch defaults" when console= is specified as "latent" consoles, and > right before starting init, if the specified one didn't work out (we > have no console with an associated tty), then go through those latent > ones and pick one that works. So, I shouldn't apply this patch? We should do something to fix this, if Debian has to drag this patch on for 5 years, that's an indication that this might be one solution we should use, right? thanks, greg k-h
On Thu, 2013-09-26 at 14:22 -0700, Greg Kroah-Hartman wrote: > So, I shouldn't apply this patch? We should do something to fix this, > if Debian has to drag this patch on for 5 years, that's an indication > that this might be one solution we should use, right? Ah sorry, dropped the ball on that one. Yes the patch is an acceptable band-aid but somebody should work on a better solution :-) Cheers, Ben.
--- a/drivers/tty/hvc/hvc_vio.c +++ b/drivers/tty/hvc/hvc_vio.c @@ -48,6 +48,7 @@ #include <asm/prom.h> #include <asm/hvsi.h> #include <asm/udbg.h> +#include <asm/machdep.h> #include "hvc_console.h" @@ -440,7 +441,9 @@ if (hvterm_priv0.proto == HV_PROTOCOL_HVSI) goto out; #endif - add_preferred_console("hvc", 0, NULL); + /* Check whether the user has requested a different console. */ + if (!strstr(cmd_line, "console=")) + add_preferred_console("hvc", 0, NULL); hvc_instantiate(0, 0, ops); out: of_node_put(stdout_node);