[PATCH] Small kernel/printk.c fix (fwd)

[James S. <jsi...@ac...>]

---------- Forwarded message ----------
Date: Fri, 30 Jun 2000 12:58:47 +0200
From: Benjamin Herrenschmidt <bh...@ca...>
To: tor...@tr..., al...@lx...
Cc: lin...@vg...
Subject: [PATCH] Small kernel/printk.c fix


Hi Linus & Alan.

Here's a small change to kernel/printk.c that I expect harmless.
Basically, it reverts the console registration mecanism to a clean state
when the last console is unregistered. It helps implementing a very small
early boot debug mecanism I use on the PPC tree that enables very-early
use of printk but which, without this patch, cause problems when the real
VT takes over.

(Since it's a small mecanism, it's implemented as a console structure,
implementing a consw would be really way too much for what it's meant for
and would bloat the code).

I usually keep this patch in my tree, but having it merged would help me
reducing the diffs between my own tree and the main one and would allow
this useful mecanism to be merged in the main PPC branch.

Here's the 2.2.x version (as of 2.2.17pre7)

--- linuxppc_2_2/kernel/printk.c	Fri Jun 30 12:00:07 2000
+++ ben_kernel/kernel/printk.c	Tue Jun 27 15:10:30 2000
@@ -468,7 +468,14 @@
 			}  
 		}
 	}
-	
+
+	/* If last console is removed, we re-enable picking the first
+	 * one that gets registered. Without that, pmac early boot console
+	 * would prevent fbcon from taking over.
+	 */
+	if (console_drivers == NULL)
+		preferred_console = -1;
+		
 	spin_unlock_irqrestore(&console_lock,flags);
 	return res;
 }

Here's the 2.4 version (as of test2)

--- printk.c.orig	Fri Jun 30 12:47:25 2000
+++ printk.c	Fri Jun 30 12:46:52 2000
@@ -471,6 +471,14 @@
 		}
 	}
 	
+	/* If last console is removed, we re-enable picking the first
+	 * one that gets registered. Without that, pmac early boot console
+	 * would prevent fbcon from taking over.
+	 */
+	if (console_drivers == NULL)
+		preferred_console = -1;
+		
+
 	spin_unlock_irqrestore(&console_lock, flags);
 	return res;
 }


Regards,
Ben.




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