[PATCH] fbdev: Remove udlfb driver

[Daniel Vetter]

On Mon, Nov 30, 2020 at 09:31:15AM -0500, Mikulas Patocka wrote:
> 
> 
> On Mon, 30 Nov 2020, Thomas Zimmermann wrote:
> 
> > Udlfb has been superseded by DRM's udl. The DRM driver is better by
> > any means and actively maintained. Remove udlfb.
> 
> Hi
> 
> I am using udlfb and it's definitely better than the DRM driver. The DRM 
> driver will crash the kernel if you unplug the device while Xorg is 
> running. The framebuffer driver doesn't crash in this case. (I have a cat 
> and the cat sometimes unplugs cables and I don't want to reboot the system 
> because of it :-)

This should be a lot better in recent kernels, there's been tons of fixes
for drm hotunplug. Might be there's still bugs in the drm/udl driver.

> The framebuffer driver is faster, it keeps back buffer and updates only 
> data that differ between the front and back buffer. The DRM driver doesn't 
> have such optimization, it will update everything in a given rectangle - 
> this increases USB traffic and makes video playback more jerky.
> 
> The framebuffer driver supports programs running full-screen directly on 
> the framebuffer console, such as web browser "links -g", image viewer 
> "fbi", postscript+pdf viewer "fbgs", ZX Spectrum emulator "fuse-sdl", 
> movie player "mplayer -vo fbdev". The DRM driver doesn't run them.

Hm this should in general work on drm drivers. Without that it's clear the
switch-over isn't really ready yet.

> If you seach for someone to maintain the framebuffer driver, I can do it.

We're looking for people to port the missing features over to the drm
drivers. The problem is that fbdev is full of security bugs, and we're
fixing them by removing the features. So that's why there's some push to
sunset at much as possible.
-Daniel

> 
> Mikulas
> 
> 
> > Signed-off-by: Thomas Zimmermann <tzimmermann at suse.de>
> > ---
> >  CREDITS                      |    5 +
> >  Documentation/fb/index.rst   |    1 -
> >  Documentation/fb/udlfb.rst   |  162 ---
> >  MAINTAINERS                  |    9 -
> >  drivers/video/fbdev/Kconfig  |   17 +-
> >  drivers/video/fbdev/Makefile |    1 -
> >  drivers/video/fbdev/udlfb.c  | 1994 ----------------------------------
> >  7 files changed, 6 insertions(+), 2183 deletions(-)
> >  delete mode 100644 Documentation/fb/udlfb.rst
> >  delete mode 100644 drivers/video/fbdev/udlfb.c
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch