ChangeSet 1.1671, 2005/06/04 18:45:49+01:00, kaf24@xxxxxxxxxxxxxxxxxxxx
Add a manual 'sync_console' boot parameter that forces synchronous
console output. May be useful for systems that crash unexpectedly
and lose the last chunk of console output.
Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>
docs/src/user.tex | 7 +++++++
xen/drivers/char/console.c | 14 ++++++++++++--
2 files changed, 19 insertions(+), 2 deletions(-)
diff -Nru a/docs/src/user.tex b/docs/src/user.tex
--- a/docs/src/user.tex 2005-06-04 14:02:45 -04:00
+++ b/docs/src/user.tex 2005-06-04 14:02:45 -04:00
@@ -1729,6 +1729,13 @@
transmitted/received character.
[NB. Default for this option is `com1,vga']
+\item [sync\_console ]
+ Force synchronous console output. This is useful if you system fails
+ unexpectedly before it has sent all available output to the
+ console. In most cases Xen will automatically enter synchronous mode
+ when an exceptional event occurs, but this option provides a manual
+ fallback.
+
\item [conswitch=$<$switch-char$><$auto-switch-char$>$ ]
Specify how to switch serial-console input between
Xen and DOM0. The required sequence is CTRL-$<$switch-char$>$
diff -Nru a/xen/drivers/char/console.c b/xen/drivers/char/console.c
--- a/xen/drivers/char/console.c 2005-06-04 14:02:45 -04:00
+++ b/xen/drivers/char/console.c 2005-06-04 14:02:45 -04:00
@@ -24,17 +24,21 @@
#include <asm/debugger.h>
#include <asm/io.h>
-/* opt_console: comma-separated list of console outputs. */
+/* console: comma-separated list of console outputs. */
static char opt_console[30] = OPT_CONSOLE_STR;
string_param("console", opt_console);
-/* opt_conswitch: a character pair controlling console switching. */
+/* conswitch: a character pair controlling console switching. */
/* Char 1: CTRL+<char1> is used to switch console input between Xen and DOM0 */
/* Char 2: If this character is 'x', then do not auto-switch to DOM0 when it */
/* boots. Any other value, or omitting the char, enables auto-switch */
static unsigned char opt_conswitch[5] = "a";
string_param("conswitch", opt_conswitch);
+/* sync_console: force synchronous console output (useful for debugging). */
+static int opt_sync_console;
+boolean_param("sync_console", opt_sync_console);
+
static int xpos, ypos;
static unsigned char *video;
@@ -437,6 +441,12 @@
XEN_COMPILER, XEN_COMPILE_DATE);
printk(" Latest ChangeSet: %s\n\n", XEN_CHANGESET);
set_printk_prefix("(XEN) ");
+
+ if ( opt_sync_console )
+ {
+ serial_start_sync(sercon_handle);
+ printk("Console output is synchronous.\n");
+ }
}
void console_endboot(int disable_vga)
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