Panels usually call drm_connector_set_panel_orientation(), which is
later than drm/kms driver calling drm_dev_register(). This leads to a
WARN()[1].

The orientation property is known earlier. For example, some panels
parse the property through device tree during probe.

The series add a panel API drm_panel_get_orientation() for drm/kms
drivers. The drivers can use the API to get panel's orientation, so they
can call drm_connector_set_panel_orientation() before drm_dev_register().

Panel needs to implement .get_orientation callback to return the property.

[1] https://patchwork.kernel.org/project/linux-mediatek/patch/20220530081910.3947168-2-hsinyi@chromium.org/

Hsin-Yi Wang (8):
  drm/panel: Add an API drm_panel_get_orientation() to return panel
    orientation
  drm/panel: boe-tv101wum-nl6: Implement .get_orientation callback
  drm/panel: panel-edp: Implement .get_orientation callback
  drm/panel: lvds: Implement .get_orientation callback
  drm/panel: panel-simple: Implement .get_orientation callback
  drm/panel: ili9881c: Implement .get_orientation callback
  drm/panel: elida-kd35t133: Implement .get_orientation callback
  drm/mediatek: Config orientation property if panel provides it

 drivers/gpu/drm/drm_panel.c                    |  9 +++++++++
 drivers/gpu/drm/mediatek/mtk_dsi.c             | 10 ++++++++++
 drivers/gpu/drm/panel/panel-boe-tv101wum-nl6.c | 14 ++++++++++++++
 drivers/gpu/drm/panel/panel-edp.c              | 15 ++++++++++++++-
 drivers/gpu/drm/panel/panel-elida-kd35t133.c   | 14 ++++++++++++++
 drivers/gpu/drm/panel/panel-ilitek-ili9881c.c  | 14 ++++++++++++++
 drivers/gpu/drm/panel/panel-lvds.c             | 15 +++++++++++++++
 drivers/gpu/drm/panel/panel-simple.c           | 16 +++++++++++++++-
 include/drm/drm_panel.h                        | 10 ++++++++++
 9 files changed, 115 insertions(+), 2 deletions(-)

-- 
2.36.1.255.ge46751e96f-goog

Hi Hsin-Yi,
thanks for this nice series.

On Mon, Jun 06, 2022 at 11:24:23PM +0800, Hsin-Yi Wang wrote:
> Panels usually call drm_connector_set_panel_orientation(), which is
> later than drm/kms driver calling drm_dev_register(). This leads to a
> WARN()[1].
> 
> The orientation property is known earlier. For example, some panels
> parse the property through device tree during probe.
> 
> The series add a panel API drm_panel_get_orientation() for drm/kms
> drivers. The drivers can use the API to get panel's orientation, so they
> can call drm_connector_set_panel_orientation() before drm_dev_register().
> 
> Panel needs to implement .get_orientation callback to return the property.

The following comment appears in every panel driver:
+       /*
+        * drm drivers are expected to call drm_panel_get_orientation() to get
+        * panel's orientation then drm_connector_set_panel_orientation() to
+        * set the property before drm_dev_register(). Otherwise there will be
+        * a WARN_ON if orientation is set after drm is registered.
+        */

Please move it to the drm_panel c or h file, it is noise to add it to
all panel drivers.

	Sam