[PATCH] drm/amdgpu: use .early_unregister hook to remove DP AUX i2c

[Grazvydas Ignotas]

When DisplayPort AUX channel i2c adapter is registered, drm_connector's
kdev member is used as a parent, so we get sysfs structure like:
  /drm/card1/card1-DP-2/i2c-12
Because of that, there is a problem when drm core (and not the driver)
calls drm_connector_unregister(), it removes parent sysfs entries
('card1-DP-2' in our example) while the i2c adapter is still registered.
Later we get a WARN when we try to unregister the i2c adapter:

  WARNING: CPU: 3 PID: 1374 at fs/sysfs/group.c:243 sysfs_remove_group+0x14c/0x150
  sysfs group ffffffff82911e40 not found for kobject 'i2c-12'

To fix it, we can use the .early_unregister hook to unregister the i2c
adapter before drm_connector's sysfs is torn down.

Signed-off-by: Grazvydas Ignotas <notasas at gmail.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
index 76a7830..09b76a8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
@@ -765,7 +765,7 @@ amdgpu_connector_lvds_detect(struct drm_connector *connector, bool force)
 	return ret;
 }
 
-static void amdgpu_connector_destroy(struct drm_connector *connector)
+static void amdgpu_connector_unregister(struct drm_connector *connector)
 {
 	struct amdgpu_connector *amdgpu_connector = to_amdgpu_connector(connector);
 
@@ -773,6 +773,12 @@ static void amdgpu_connector_destroy(struct drm_connector *connector)
 		drm_dp_aux_unregister(&amdgpu_connector->ddc_bus->aux);
 		amdgpu_connector->ddc_bus->has_aux = false;
 	}
+}
+
+static void amdgpu_connector_destroy(struct drm_connector *connector)
+{
+	struct amdgpu_connector *amdgpu_connector = to_amdgpu_connector(connector);
+
 	amdgpu_connector_free_edid(connector);
 	kfree(amdgpu_connector->con_priv);
 	drm_connector_unregister(connector);
@@ -826,6 +832,7 @@ static const struct drm_connector_funcs amdgpu_connector_lvds_funcs = {
 	.dpms = drm_helper_connector_dpms,
 	.detect = amdgpu_connector_lvds_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
+	.early_unregister = amdgpu_connector_unregister,
 	.destroy = amdgpu_connector_destroy,
 	.set_property = amdgpu_connector_set_lcd_property,
 };
@@ -936,6 +943,7 @@ static const struct drm_connector_funcs amdgpu_connector_vga_funcs = {
 	.dpms = drm_helper_connector_dpms,
 	.detect = amdgpu_connector_vga_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
+	.early_unregister = amdgpu_connector_unregister,
 	.destroy = amdgpu_connector_destroy,
 	.set_property = amdgpu_connector_set_property,
 };
@@ -1203,6 +1211,7 @@ static const struct drm_connector_funcs amdgpu_connector_dvi_funcs = {
 	.detect = amdgpu_connector_dvi_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.set_property = amdgpu_connector_set_property,
+	.early_unregister = amdgpu_connector_unregister,
 	.destroy = amdgpu_connector_destroy,
 	.force = amdgpu_connector_dvi_force,
 };
@@ -1493,6 +1502,7 @@ static const struct drm_connector_funcs amdgpu_connector_dp_funcs = {
 	.detect = amdgpu_connector_dp_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.set_property = amdgpu_connector_set_property,
+	.early_unregister = amdgpu_connector_unregister,
 	.destroy = amdgpu_connector_destroy,
 	.force = amdgpu_connector_dvi_force,
 };
@@ -1502,6 +1512,7 @@ static const struct drm_connector_funcs amdgpu_connector_edp_funcs = {
 	.detect = amdgpu_connector_dp_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.set_property = amdgpu_connector_set_lcd_property,
+	.early_unregister = amdgpu_connector_unregister,
 	.destroy = amdgpu_connector_destroy,
 	.force = amdgpu_connector_dvi_force,
 };
-- 
2.7.4