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authorGreg Edwards <edwardsg@sgi.com>2005-06-23 03:09:05 -0400
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-06-23 12:45:18 -0400
commitab4af03a4054bd78bcabfb2214c9597201beae35 (patch)
tree43d2b273cb84349bfdde6667f8d5fea1d2d87031
parentdfe52244e004f5103478966cd88351feb5c50d79 (diff)
[PATCH] CON_CONSDEV bit not set correctly on last console
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 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. Signed-off-by: Greg Edwards <edwardsg@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
-rw-r--r--kernel/printk.c12
1 files changed, 10 insertions, 2 deletions
diff --git a/kernel/printk.c b/kernel/printk.c
index 01b58d7d17ff..3a442bfb8bee 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -876,8 +876,10 @@ void register_console(struct console * console)
876 break; 876 break;
877 console->flags |= CON_ENABLED; 877 console->flags |= CON_ENABLED;
878 console->index = console_cmdline[i].index; 878 console->index = console_cmdline[i].index;
879 if (i == preferred_console) 879 if (i == selected_console) {
880 console->flags |= CON_CONSDEV; 880 console->flags |= CON_CONSDEV;
881 preferred_console = selected_console;
882 }
881 break; 883 break;
882 } 884 }
883 885
@@ -897,6 +899,8 @@ void register_console(struct console * console)
897 if ((console->flags & CON_CONSDEV) || console_drivers == NULL) { 899 if ((console->flags & CON_CONSDEV) || console_drivers == NULL) {
898 console->next = console_drivers; 900 console->next = console_drivers;
899 console_drivers = console; 901 console_drivers = console;
902 if (console->next)
903 console->next->flags &= ~CON_CONSDEV;
900 } else { 904 } else {
901 console->next = console_drivers->next; 905 console->next = console_drivers->next;
902 console_drivers->next = console; 906 console_drivers->next = console;
@@ -937,10 +941,14 @@ int unregister_console(struct console * console)
937 /* If last console is removed, we re-enable picking the first 941 /* If last console is removed, we re-enable picking the first
938 * one that gets registered. Without that, pmac early boot console 942 * one that gets registered. Without that, pmac early boot console
939 * would prevent fbcon from taking over. 943 * would prevent fbcon from taking over.
944 *
945 * If this isn't the last console and it has CON_CONSDEV set, we
946 * need to set it on the next preferred console.
940 */ 947 */
941 if (console_drivers == NULL) 948 if (console_drivers == NULL)
942 preferred_console = selected_console; 949 preferred_console = selected_console;
943 950 else if (console->flags & CON_CONSDEV)
951 console_drivers->flags |= CON_CONSDEV;
944 952
945 release_console_sem(); 953 release_console_sem();
946 return res; 954 return res;