On 27-08-20, 14:20, Yue Hu wrote:
> Currenly, drivers/video/backlight does not call
> thermal_of_cooling_device_register()
> to register thermal cooling device. The issue happened in msm-4.19 kernel for
> QCOM/Android platform. Backlight in msm-4.19 kernel will register thermal
> cooling
> device as below:
>
> +static int bd_cdev_get_max_brightness(struct thermal_cooling_device *cdev,
> + unsigned long *state)
> +{
> + struct backlight_device *bd = (struct backlight_device *)cdev->devdata;
> +
> + *state = bd->props.max_brightness;
> +
> + return 0;
> +}
>
>
> +static struct thermal_cooling_device_ops bd_cdev_ops = {
> + .get_max_state = bd_cdev_get_max_brightness,
>
> +static void backlight_cdev_register(struct device *parent,
> + struct backlight_device *bd)
> +{
> + if (of_find_property(parent->of_node, "#cooling-cells", NULL)) {
> + bd->cdev = thermal_of_cooling_device_register(parent->of_node,
> + (char *)dev_name(&bd->dev), bd, &bd_cdev_ops);
>
> And the bd->props.max_brightness is getting from video/backlight/qcom-wled.c.
> Maybe
> the driver should not assign 1024 to states/max_brightness. I'm not sure
> about it.
> So i consider to change memory allocation methord. That's the origin of the
> patch.
Thanks for the details. So this is not about upstream tree, as a rule
we aren't going to make changes here for any downstream tree.
Now coming back to the downstream driver, I also don't see a point in
returning bd->props.max_brightness as the max number of states there.
Maybe have 10 states, each occupying bd->props.max_brightness/10
brightness and so you will end up with 10 states only. But yeah,
whatever downstream decides on that.
--
viresh
