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 37c4993..7472613 100644 (file)
--- 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]);