From: Paul Fox <pgf@laptop.org>
Date: Fri, 1 Oct 2010 17:17:19 +0000 (+0100)
Subject: x86, olpc: Don't retry EC commands forever
X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=286e5b97eb22baab9d9a41ca76c6b933a484252c;p=deliverable%2Flinux.git

x86, olpc: Don't retry EC commands forever

Avoids a potential infinite loop.

It was observed once, during an EC hacking/debugging
session - not in regular operation.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Cc: dilinger@queued.net
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
---

diff --git a/arch/x86/kernel/olpc.c b/arch/x86/kernel/olpc.c
index 37c49934c785..747261302598 100644
--- a/arch/x86/kernel/olpc.c
+++ b/arch/x86/kernel/olpc.c
@@ -114,6 +114,7 @@ int olpc_ec_cmd(unsigned char cmd, unsigned char *inbuf, size_t inlen,
 	unsigned long flags;
 	int ret = -EIO;
 	int i;
+	int restarts = 0;
 
 	spin_lock_irqsave(&ec_lock, flags);
 
@@ -169,7 +170,9 @@ restart:
 			if (wait_on_obf(0x6c, 1)) {
 				printk(KERN_ERR "olpc-ec:  timeout waiting for"
 						" EC to provide data!\n");
-				goto restart;
+				if (restarts++ < 10)
+					goto restart;
+				goto err;
 			}
 			outbuf[i] = inb(0x68);
 			pr_devel("olpc-ec:  received 0x%x\n", outbuf[i]);