On Wed, Nov 30, 2011 at 06:46:19PM +0000, Pawel Moll wrote:

On Wed, 2011-11-30 at 15:58 +0000, Dave Martin wrote:

quoted

Now that a person may fail to boot on a supported board simply due to
failing to supply a device tree, it may be a good idea to have a more
helpful panic message for that situation, perhaps something like the
following.

If you don't think this fits in this series, I can always follow up 
later.

diff --git a/arch/arm/mach-vexpress/v2m.c b/arch/arm/mach-vexpress/v2m.c
index 6965f64..9dda482 100644
--- a/arch/arm/mach-vexpress/v2m.c
+++ b/arch/arm/mach-vexpress/v2m.c

@@ -434,8 +434,11 @@ static void __init v2m_populate_ct_desc(void)
 			ct_desc = ct_descs[i];
 
 	if (!ct_desc)
-		panic("vexpress: failed to populate core tile description "
-		      "for tile ID 0x%8x\n", current_tile_id);
+		panic("vexpress: this kernel does not support core tile ID "
+		      "0x%08x when booting via ATAGs.\n"
+		      "You may need a device tree blob or a different kernel "
+		      "to boot on this board.\n",
+		      current_tile_id);
 }
 
 static void __init v2m_map_io(void)

No, that's cool with me, will add that. Thanks!

I just discovered that Documentation/CodingStyle recommends not to split printk
strings onto multiple lines, for easier grepping.  Sounds like sensible advice,
so maybe just split at "\n":

quoted

+		panic("vexpress: this kernel does not support core tile ID 0x%08x when booting via ATAGs.\n" 
+		      "You may need a device tree blob or a different kernel to boot on this board.\n",
+		      current_tile_id);

Cheers
---Dave