drm/fb-helper: Remove drm_fb_helper_crtc

struct drm_fb_helper_crtc is now just a wrapper around drm_mode_set so
use that directly instead and attach it as a modeset array onto
drm_client_dev. drm_fb_helper will use this array to store its modesets
which means it will always initialize a drm_client, but it will not
register the client (callbacks) unless it's the generic fbdev emulation.

Code will later be moved to drm_client, so add code there in a new file
drm_client_modeset.c with MIT license to match drm_fb_helper.c.

The modeset connector array size is hardcoded for the cloned case to avoid
having to pass in a value from the driver. A value of 8 is chosen to err
on the safe side. This means that the max connector argument for
drm_fb_helper_init() and drm_fb_helper_fbdev_setup() isn't used anymore,
a todo entry for this is added.

In pan_display_atomic() restore_fbdev_mode_force() is used instead of
restore_fbdev_mode_atomic() because that one will later become internal
to drm_client_modeset.

Locking order:
1. drm_fb_helper->lock
2. drm_master_internal_acquire
3. drm_client_dev->modeset_mutex

v6: Improve commit message (Sam Ravnborg)

v3:
- Use full drm_client_init/release for the modesets (Daniel Vetter)
- drm_client_for_each_modeset: use lockdep_assert_held (Daniel Vetter)
- Hook up to Documentation/gpu/drm-client.rst (Daniel Vetter)

v2:
- Add modesets array to drm_client (Daniel Vetter)
- Use a new file for the modeset code (Daniel Vetter)
- File has to be MIT licensed (Emmanuel Vadot)
- Add copyrights from drm_fb_helper.c

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20190531140117.37751-3-noralf@tronnes.org

2 files changed, 6 insertions, 0 deletions

diff --git a/Documentation/gpu/drm-client.rst b/Documentation/gpu/drm-client.rst
index 7e672063e7eb..58b5a1d1219d 100644
--- a/Documentation/gpu/drm-client.rst
+++ b/Documentation/gpu/drm-client.rst
@@ -10,3 +10,6 @@ Kernel clients
 
 .. kernel-doc:: drivers/gpu/drm/drm_client.c
    :export:
+
+.. kernel-doc:: drivers/gpu/drm/drm_client_modeset.c
+   :export:
diff --git a/Documentation/gpu/todo.rst b/Documentation/gpu/todo.rst
index 66f05f4e469f..9d4038c50013 100644
--- a/Documentation/gpu/todo.rst
+++ b/Documentation/gpu/todo.rst
@@ -289,6 +289,9 @@ drm_fb_helper tasks
   these igt tests need to be fixed: kms_fbcon_fbt@psr and
   kms_fbcon_fbt@psr-suspend.
 
+- The max connector argument for drm_fb_helper_init() and
+  drm_fb_helper_fbdev_setup() isn't used anymore and can be removed.
+
 Core refactorings
 =================