[PATCH 0/6] drm/tinydrm: Support device unplug

[Daniel Vetter]

Hi Noralf,

On Mon, Aug 28, 2017 at 07:17:42PM +0200, Noralf Trønnes wrote:
> This adds device unplug support to drm_fb_helper, drm_fb_cma_helper
> (fbdev) and tinydrm.
> 
> My motivation for doing this is to make tinydrm useable with USB
> devices. This discussion gave insight into the problem:
> [PATCH v5 2/6] drm/bridge: Add a devm_ allocator for panel bridge.
> https://lists.freedesktop.org/archives/dri-devel/2017-August/149376.html

Looks a lot less scary than I thought, but I think needs a bit more
polish.

I think it'd be also great if you could co-evolve the udl driver to get
this right, since it looks like right now it'll just oops when you unplug
when userspace is using the fbdev emulation. That way we'd be at least
somewhat consistent with unpluggable drivers, and since it's only 1 other
it should be doable. Unplugging is already hard, having 2 drivers do stuff
differently (when we only have 2 with unplug support) pretty much
guarnatees we'll never get this right.

But maybe good to first develop this using your own driver only.

Cheers, Daniel

> 
> Noralf.
> 
> Noralf Trønnes (6):
>   drm/fb-helper: Avoid NULL ptr dereference in fb_set_suspend()
>   drm/fb-helper: Support device unplug
>   drm/fb-cma-helper: Support device unplug
>   drm/tinydrm: Embed drm_device in tinydrm_device
>   drm/tinydrm/mi0283qt: Let the display pipe handle power
>   drm/tinydrm: Support device unplug
> 
>  drivers/gpu/drm/drm_fb_cma_helper.c         | 139 +++++++++----------
>  drivers/gpu/drm/drm_fb_helper.c             | 207 +++++++++++++++++++++++++++-
>  drivers/gpu/drm/tinydrm/core/tinydrm-core.c | 109 ++++++++++-----
>  drivers/gpu/drm/tinydrm/core/tinydrm-pipe.c |   2 +-
>  drivers/gpu/drm/tinydrm/mi0283qt.c          |  77 +++--------
>  drivers/gpu/drm/tinydrm/mipi-dbi.c          |  27 ++--
>  drivers/gpu/drm/tinydrm/repaper.c           |  19 ++-
>  drivers/gpu/drm/tinydrm/st7586.c            |  25 ++--
>  include/drm/drm_fb_cma_helper.h             |   1 +
>  include/drm/drm_fb_helper.h                 |  35 +++++
>  include/drm/tinydrm/tinydrm.h               |  14 +-
>  11 files changed, 460 insertions(+), 195 deletions(-)
> 
> -- 
> 2.7.4
> 

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