[PATCH v3 0/1] DRM fbconv helpers for converting fbdev drivers

[PATCH v3 0/1] DRM fbconv helpers for converting fbdev drivers

[Thomas Zimmermann]

I rebased v2 of this patchset onto v5.3 and uploaded the result
into the git repo at

  https://gitlab.freedesktop.org/tzimmermann/linux/tree/fbconv

I'll keep the helpers updated for new Linux releases from time to
time. The attached patch adds a new item to the TODO list that refers
to the external tree and documentation.

v3:
	* replace patchset in favor of TODO item that refers to
	  external tree
v2:
	* rename to fbconv helpers
	* rewrite as helper library
	* switch over to simple KMS helpers
	* switch over to SHMEM
	* add documentation

Thomas Zimmermann (1):
  drm: Add TODO item for fbdev driver conversion

 Documentation/gpu/todo.rst | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

--
2.23.0

[PATCH v3 1/1] drm: Add TODO item for fbdev driver conversion

[Thomas Zimmermann]

The DRM TODO list now contains an entry for converting fbdev
drivers over to DRM.

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
---
 Documentation/gpu/todo.rst | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index 79785559d711..23b3a67794ba 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -462,3 +462,30 @@ Contact: Sam Ravnborg
 
 Outside DRM
 ===========
+
+Convert fbdev drivers to DRM
+----------------------------
+
+There are plenty of fbdev drivers for older hardware. Some hwardware has
+become obsolete, but some still provides good(-enough) framebuffers. The
+drivers that are still useful should be converted to DRM and afterwards
+removed from fbdev.
+
+Very simple fbdev drivers can best be converted by starting with a new
+DRM driver. Simple KMS helpers and SHMEM should be able to handle any
+existing hardware. The new driver's call-back functions are filled from
+existing fbdev code.
+
+More complex fbdev drivers can be refactored step-by-step into a DRM
+driver with the help of the DRM fbconv helpers. [1] These helpers provide
+the transition layer between the DRM core infrastructure and the fbdev
+driver interface. Create a new DRM driver on top of the fbconv helpers,
+copy over the fbdev driver, and hook it up to the DRM code. Examples for
+several fbdev drivers are available at [1] and a tutorial of this process
+available at [2]. The result is a primitive DRM driver that can run X11
+and Weston.
+
+ - [1] https://gitlab.freedesktop.org/tzimmermann/linux/tree/fbconv
+ - [2] https://gitlab.freedesktop.org/tzimmermann/linux/blob/fbconv/drivers/gpu/drm/drm_fbconv_helper.c
+
+Contact: Thomas Zimmermann <tzimmermann@suse.de>
-- 
2.23.0

Re: [PATCH v3 1/1] drm: Add TODO item for fbdev driver conversion

[Daniel Vetter]

On Thu, Oct 17, 2019 at 09:47:05AM +0200, Thomas Zimmermann wrote:
> The DRM TODO list now contains an entry for converting fbdev
> drivers over to DRM.
> 
> Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>

> ---
>  Documentation/gpu/todo.rst | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
> index 79785559d711..23b3a67794ba 100644
> --- a/Documentation/gpu/todo.rst
> +++ b/Documentation/gpu/todo.rst
> @@ -462,3 +462,30 @@ Contact: Sam Ravnborg
>  
>  Outside DRM
>  ===========
> +
> +Convert fbdev drivers to DRM
> +----------------------------
> +
> +There are plenty of fbdev drivers for older hardware. Some hwardware has
> +become obsolete, but some still provides good(-enough) framebuffers. The
> +drivers that are still useful should be converted to DRM and afterwards
> +removed from fbdev.
> +
> +Very simple fbdev drivers can best be converted by starting with a new
> +DRM driver. Simple KMS helpers and SHMEM should be able to handle any
> +existing hardware. The new driver's call-back functions are filled from
> +existing fbdev code.
> +
> +More complex fbdev drivers can be refactored step-by-step into a DRM
> +driver with the help of the DRM fbconv helpers. [1] These helpers provide
> +the transition layer between the DRM core infrastructure and the fbdev
> +driver interface. Create a new DRM driver on top of the fbconv helpers,
> +copy over the fbdev driver, and hook it up to the DRM code. Examples for
> +several fbdev drivers are available at [1] and a tutorial of this process
> +available at [2]. The result is a primitive DRM driver that can run X11
> +and Weston.
> +
> + - [1] https://gitlab.freedesktop.org/tzimmermann/linux/tree/fbconv
> + - [2] https://gitlab.freedesktop.org/tzimmermann/linux/blob/fbconv/drivers/gpu/drm/drm_fbconv_helper.c

btw if you want to push a patch to get this built and published:

https://gitlab.freedesktop.org/drm/igt-gpu-tools/blob/master/.gitlab-ci.yml

The "pages" job is the one which gets published to

https://drm.pages.freedesktop.org/igt-gpu-tools/

With that you could point at the pretty hmtl even.
-Daniel

> +
> +Contact: Thomas Zimmermann <tzimmermann@suse.de>
> -- 
> 2.23.0
> 

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch