wscon message buffer

[T <bobs%thelibertytree.org@localhost>]

Howdy,
I figured posting this patch will help folks with reading messages from the boot
process while using some of the non-default kernel options for debugging. The
current message buffer works okay for a standard boot, but the message buffer is
too small for things like dumping residual data and PCI configuration
information. The macppc port uses this patched value (8) as the default vs the
value (2) used by prep port.
-------------file-start---------------------------------------------------------
--- src/sys/arch/prep/include/param.h	2021-06-23 00:41:15.897227843 -0600
+++ param.h				2021-06-23 00:46:27.257472450 -0600
@@ -40,6 +40,10 @@
 #define        KERNBASE                0x100000
 #define        __NO_FIXED_MSGBUF

+#ifndef MSGBUFSIZE
+#define        MSGBUFSIZE              (8*NBPG)
+#endif
+
 #endif /* _KERNEL && !_MODULE */

 /* at this offset we mmap() the PCI IO range in display drivers */
--------------file-end----------------------------------------------------------

If you're using wscon instead of serial console, enabling the kernel option:
options		WSDISPLAY_SCROLLSUPPORT
may also be useful.

One noticeable problem while using wscon is the "less" pager only updates the
very top line when attempting to scroll back using the up-arrow key. Scrolling
forward works fine, the problem only exists in the reverse direction. This
problem also occurs with 'man' and 'vi', which may be using the same
functionality. Anyone else see this?