[PATCH 56/59] drm/todo: Update backlight todo

[Daniel Thompson]

On 14/06/2019 21:36, Daniel Vetter wrote:
> Basic helpers have been extracted, now there's a pile more todo still
> across the entire tree.
> 
> Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>

No disagreement here... so FWIW:

Reviewed-by: Daniel Thompson <daniel.thompson at linaro.org>


Daniel.

> ---
>   Documentation/gpu/todo.rst | 27 +++++++++++++--------------
>   1 file changed, 13 insertions(+), 14 deletions(-)
> 
> diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
> index 21a7b7800d3e..c4e7c0672a14 100644
> --- a/Documentation/gpu/todo.rst
> +++ b/Documentation/gpu/todo.rst
> @@ -422,6 +422,19 @@ fit the available time.
>   
>   Contact: Daniel Vetter
>   
> +Backlight Refactoring
> +---------------------
> +
> +Backlight drivers have a triple enable/disable state, which is a bit overkill.
> +Plan to fix this:
> +
> +1. Roll out backlight_enable() and backlight_disable() helpers everywhere. This
> +   has started already.
> +2. In all, only look at one of the three status bits set by the above helpers.
> +3. Remove the other two status bits.
> +
> +Contact: Daniel Vetter
> +
>   Driver Specific
>   ===============
>   
> @@ -431,20 +444,6 @@ tinydrm
>   Tinydrm is the helper driver for really simple fb drivers. The goal is to make
>   those drivers as simple as possible, so lots of room for refactoring:
>   
> -- backlight helpers, probably best to put them into a new drm_backlight.c.
> -  This is because drivers/video is de-facto unmaintained. We could also
> -  move drivers/video/backlight to drivers/gpu/backlight and take it all
> -  over within drm-misc, but that's more work. Backlight helpers require a fair
> -  bit of reworking and refactoring. A simple example is the enabling of a backlight.
> -  Tinydrm has helpers for this. It would be good if other drivers can also use the
> -  helper. However, there are various cases we need to consider i.e different
> -  drivers seem to have different ways of enabling/disabling a backlight.
> -  We also need to consider the backlight drivers (like gpio_backlight). The situation
> -  is further complicated by the fact that the backlight is tied to fbdev
> -  via fb_notifier_callback() which has complicated logic. For further details, refer
> -  to the following discussion thread:
> -  https://groups.google.com/forum/#!topic/outreachy-kernel/8rBe30lwtdA
> -
>   - spi helpers, probably best put into spi core/helper code. Thierry said
>     the spi maintainer is fast&reactive, so shouldn't be a big issue.
>   
>