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Date: Mon, 20 Oct 2014 11:27:02 -0700
From: Stephen Boyd <sboyd@codeaurora.org>
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To: Kumar Gala <galak@codeaurora.org>
CC: gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org,
        linux-arm-msm <linux-arm-msm@vger.kernel.org>,
        linux-arm-kernel@lists.infradead.org, Rob Herring <robh@kernel.org>
Subject: Re: [PATCH] tty: serial: msm: Fix lock init issue with earlycon
References: <1413551588-14877-1-git-send-email-galak@codeaurora.org>
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On 10/17/2014 06:13 AM, Kumar Gala wrote:
> With CONFIG_DEBUG_SPINLOCK enabled we see:
>
> BUG: spinlock bad magic on CPU#0, swapper/0
>   lock: early_console_dev+0x8/0x160, .magic: 00000000, .owner: <none>/-1, .owner_cpu: 0
> CPU: 0 PID: 0 Comm: swapper Not tainted 3.17.0-09733-gb446b33-dirty #18

[...]

> diff --git a/drivers/tty/serial/msm_serial.c b/drivers/tty/serial/msm_serial.c
> index 4b6c783..8ab27c9 100644
> --- a/drivers/tty/serial/msm_serial.c
> +++ b/drivers/tty/serial/msm_serial.c
> @@ -973,6 +973,8 @@ msm_serial_early_console_setup(struct earlycon_device *device, const char *opt)
>   	if (!device->port.membase)
>   		return -ENODEV;
>   
> +	spin_lock_init(&device->port.lock);
> +
>   	device->con->write = msm_serial_early_write;
>   	return 0;
>   }
> @@ -995,6 +997,8 @@ msm_serial_early_console_setup_dm(struct earlycon_device *device,
>   	if (!device->port.membase)
>   		return -ENODEV;
>   
> +	spin_lock_init(&device->port.lock);
> +
>   	device->con->write = msm_serial_early_write_dm;
>   	return 0;
>   }

Could this be done in the tty core instead?

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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