summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
-rw-r--r--Documentation/kernel-parameters.txt6
-rw-r--r--kernel/printk.c16
2 files changed, 21 insertions, 1 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index e9261e938f6a..c357a31411cd 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -872,6 +872,12 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
If specified, z/VM IUCV HVC accepts connections
from listed z/VM user IDs only.
+ keep_bootcon [KNL]
+ Do not unregister boot console at start. This is only
+ useful for debugging when something happens in the window
+ between unregistering the boot console and initializing
+ the real console.
+
i2c_bus= [HW] Override the default board specific I2C bus speed
or register an additional I2C bus that is not
registered from board initialization code.
diff --git a/kernel/printk.c b/kernel/printk.c
index 33284adb2189..2b591f252e55 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1316,6 +1316,18 @@ void console_start(struct console *console)
}
EXPORT_SYMBOL(console_start);
+static int __read_mostly keep_bootcon;
+
+static int __init keep_bootcon_setup(char *str)
+{
+ keep_bootcon = 1;
+ printk(KERN_INFO "debug: skip boot console de-registration.\n");
+
+ return 0;
+}
+
+early_param("keep_bootcon", keep_bootcon_setup);
+
/*
* The console driver calls this routine during kernel initialization
* to register the console printing procedure with printk() and to
@@ -1463,7 +1475,9 @@ void register_console(struct console *newcon)
* users know there might be something in the kernel's log buffer that
* went to the bootconsole (that they do not see on the real console)
*/
- if (bcon && ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV)) {
+ if (bcon &&
+ ((newcon->flags & (CON_CONSDEV | CON_BOOT)) == CON_CONSDEV) &&
+ !keep_bootcon) {
/* we need to iterate through twice, to make sure we print
* everything out, before we unregister the console(s)
*/