Gosh, that part of printk is really complex.
On (19/11/14 10:57), Petr Mladek wrote:
> For a proper solution we would need to match boot and real
> consoles that write messages into the physical device.
> But I am afraid that there is no support for this.
Wouldn't those have same tty driver?
---
kernel/printk/printk.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index f1b08015d3fa..a84cb20acf42 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2690,6 +2690,19 @@ static int __init keep_bootcon_setup(char *str)
early_param("keep_bootcon", keep_bootcon_setup);
+static bool known_console_driver(struct console *newcon)
+{
+ struct console *con;
+
+ for_each_console(con) {
+ if (!(con->flags & CON_ENABLED))
+ continue;
+ if (con->device && con->device == newcon->device)
+ return true;
+ }
+ return false;
+}
+
/*
* The console driver calls this routine during kernel initialization
* to register the console printing procedure with printk() and to
@@ -2828,6 +2841,9 @@ void register_console(struct console *newcon)
if (newcon->flags & CON_EXTENDED)
nr_ext_console_drivers++;
+ if (known_console_driver(newcon))
+ newcon->flags &= ~CON_PRINTBUFFER;
+
if (newcon->flags & CON_PRINTBUFFER) {
/*
* console_unlock(); will print out the buffered messages
