On Wed, Apr 06, 2005 at 03:53:17PM -0700, Andrew Morton wrote: | Greg Edwards <[EMAIL PROTECTED]> wrote: | > | > According to include/linux/console.h, CON_CONSDEV flag should be set on | > the last console specified on the boot command line: | > | > 86 #define CON_PRINTBUFFER (1) | > 87 #define CON_CONSDEV (2) /* Last on the command line */ | > 88 #define CON_ENABLED (4) | > 89 #define CON_BOOT (8) | > | > This does not currently happen if there is more than one console specified | > on the boot commandline. Instead, it gets set on the first console on the | > command line. This can cause problems for things like kdb that look for | > the CON_CONSDEV flag to see if the console is valid. | > | > Additionaly, it doesn't look like CON_CONSDEV is reassigned to the next | > preferred console at unregister time if the console being unregistered | > currently has that bit set. | > | > Example (from sn2 ia64): | > | > elilo vmlinuz root=<dev> console=ttyS0 console=ttySG0 | > | > in this case, the flags on ttySG console struct will be 0x4 (should be | > 0x6). | > | > Attached patch against bk fixes both issues for the cases I looked at. It | > uses selected_console (which gets incremented for each console specified | > on the command line) as the indicator of which console to set CON_CONSDEV | > on. When adding the console to the list, if the previous one had | > CON_CONSDEV set, it masks it out. Tested on ia64 and x86. | | The `console=a console=b' behaviour seem basically random to me :(. And it | gets re-randomised on a regular basis. | | I wonder if we should leave the existing behaviour alone (continue to set | CON_CONSDEV on the first console) and just change the documentation? | That'll minimise the disruption which we cause.
The problem with the current behavior is it breaks overriding the default from the boot line. In the ia64 case, there may be a global append line defining console=a in elilo.conf. Then you want to boot your kernel, and want to override the default by passing console=b on the boot line. elilo constructs the kernel cmdline by starting with the value of the global append line, then tacks on whatever else you specify, which puts console=b last. You can always edit the elilo.conf and change the global value, but that seems like a pretty big hammer for something you may just want to test. Greg - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
