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

Daniel Vetter
2019-06-14T20:37:28Z

Basic helpers have been extracted, now there's a pile more todo still
across the entire tree.

Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
---
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.

--
2.20.1