[POWERPC] Fix builtin command line interaction with firmware

It seems that prom_init's early_cmdline_parse is broken on at least
Apple 970 xserves and IBM JS20 blades with SLOF.  The firmware of these
machines returns -1 and 1 respectively when getprop is called for the
bootargs property of /chosen, causing Linux to ignore its builtin
command line in favor of a null string.  This patch makes Linux use its
builtin command line if getprop returns an error or a null string.

Signed-off-by: Amos Waterland <apw@us.ibm.com>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/powerpc/kernel/prom_init.c b/arch/powerpc/kernel/prom_init.c
index 57d8a16438a0..8c28eb0cbdac 100644
--- a/arch/powerpc/kernel/prom_init.c
+++ b/arch/powerpc/kernel/prom_init.c
@@ -567,7 +567,7 @@ static void __init early_cmdline_parse(void)
         if ((long)_prom->chosen > 0)
                 l = prom_getprop(_prom->chosen, "bootargs", p, COMMAND_LINE_SIZE-1);
 #ifdef CONFIG_CMDLINE
-        if (l == 0) /* dbl check */
+        if (l <= 0 || p[0] == '\0') /* dbl check */
                 strlcpy(RELOC(prom_cmd_line),
                         RELOC(CONFIG_CMDLINE), sizeof(prom_cmd_line));
 #endif /* CONFIG_CMDLINE */