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From: Paul Fulghum <paulkf@microgate.com>
To: Ingo Molnar <mingo@elte.hu>
Cc: Steven Rostedt <rostedt@goodmis.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH -rt] buggy UART fix
Date: Tue, 28 Feb 2006 15:26:26 -0600	[thread overview]
Message-ID: <1141161986.2914.2.camel@amdx2.microgate.com> (raw)
In-Reply-To: <20060228204059.GA1825@elte.hu>

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


      reply	other threads:[~2006-02-28 21:26 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-02-27 15:24 [PATCH -rt] buggy UART fix Steven Rostedt
2006-02-28 19:45 ` Ingo Molnar
2006-02-28 20:40   ` Ingo Molnar
2006-02-28 21:26     ` Paul Fulghum [this message]

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