Re: [PATCH -rt] buggy UART fix

[Paul Fulghum <paulkf@microgate.com>]

On Tue, 2006-02-28 at 21:40 +0100, Ingo Molnar wrote:
> hm, i just got the deadlock below, most likely due to your serial fix.  
> (never got this before) It's not 100% reproducible - booted the kernel a 
> dozen times (with your patch applied, working on other stuff) before i 
> got this deadlock.

The original patch grabs the port.lock and then
calls serial8250_handle_port() which grabs the lock
again. Just remove the spin_lock/spin_unlock below.

+ /*
+ * If we have a buggy TX line, that doesn't
+ * notify us via iir that we need to transmit
+ * then force the call.
+ */
+ if (!handled && (up->bugs & UART_BUG_TXEN)) {
+ spin_lock(&up->port.lock);
+ serial8250_handle_port(up, regs);
+ spin_unlock(&up->port.lock);
+ }

-- 
Paul Fulghum
Microgate Systems, Ltd

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