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Message-ID: <d120d50005082615445557d776@mail.gmail.com>
Date: Fri, 26 Aug 2005 17:44:39 -0500
From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reply-To: dtor_core@ameritech.net
To: Robert Love <rml@novell.com>
Subject: Re: [patch] IBM HDAPS accelerometer driver, with probing.
Cc: Andrew Morton <akpm@osdl.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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On 8/26/05, Robert Love <rml@novell.com> wrote:

> +static void hdaps_calibrate(void)
> +{
> +       int x, y, ret;
> +
> +       ret = accelerometer_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y);
> +       if (unlikely(ret))
> +               return;
> +
> +       rest_x = x;
> +       rest_y = y;
> +}

Is this function used in a hot path to warrant using "unlikely"? There
are to many "unlikely" in the code for my taste.

> +
> +static ssize_t hdaps_mousedev_store(struct device *dev,
> +                                   struct device_attribute *attr,
> +                                   const char *buf, size_t count)
> +{
> +       int enable;
> +
> +       if (sscanf(buf, "%d", &enable) != 1)
> +               return -EINVAL;
> +
> +       spin_lock(&hdaps_lock);
> +       if (enable == 1)
> +               hdaps_mousedev_enable();
> +       else if (enable == 0)
> +               hdaps_mousedev_disable();
> +       spin_unlock(&hdaps_lock);
> +
> +       return count;
> +}

input_[un]register_device and del_timer_sync are "long" operations. I
think a semaphore would be better here.

-- 
Dmitry