Michael Hanselmann <[EMAIL PROTECTED]> wrote:
>
> +#include <asm/semaphore.h>
backlight_device would appear to need mutex conversion.
Then again, maybe we take backlight_device.sem recursively - I do recall
some pretty wild happenings in there.
> +static void appledisplay_work(void *private)
> +{
> + struct appledisplay *pdata = private;
> + int retval;
> +
> + up(&pdata->bd->sem);
> + retval = appledisplay_bl_get_brightness(pdata->bd);
> + if (retval >= 0)
> + pdata->bd->props->brightness = retval;
> + down(&pdata->bd->sem);
> +
> + /* Poll again in about 125ms if there's still a button pressed */
> + if (pdata->button_pressed)
> + schedule_delayed_work(&pdata->work, HZ / 8);
> +}
Gee it's odd to go upping a semaphore on entry to a schedule_work()
handler. What's going on here?
> +static int appledisplay_probe(struct usb_interface *iface,
> + const struct usb_device_id *id)
> +{
>
> ..
>
> + /* Try to get brightness */
> + up(&pdata->bd->sem);
> + brightness = appledisplay_bl_get_brightness(pdata->bd);
> + down(&pdata->bd->sem);
This looks fishy too. appledisplay_bl_get_brightness() doesn't appear to
take that semaphore, so why drop the lock?
> + if (brightness < 0) {
> + retval = brightness;
> + err("appledisplay: Error while getting initial brightness: %d",
> retval);
> + goto error;
> + }
> +
> + /* Set brightness in backlight device */
> + up(&pdata->bd->sem);
> + pdata->bd->props->brightness = brightness;
> + down(&pdata->bd->sem);
Ditto. If it's attempting to synchronise against appledisplay_work() in
some way then I'd have thought it was racy..
> +config USB_APPLEDISPLAY
I have such a display - shall try to remember to test the driver, thanks.
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