[PATCH] drm/amdgpu/display: Fix reload driver error

[Kazlauskas, Nicholas]

On 5/28/19 6:28 AM, Emily Deng wrote:
> Issue:
> Will have follow error when reload driver:
> [ 3986.567739] sysfs: cannot create duplicate filename '/devices/pci0000:00/0000:00:07.0/drm_dp_aux_dev'
> [ 3986.567743] CPU: 6 PID: 1767 Comm: modprobe Tainted: G           OE     5.0.0-rc1-custom #1
> [ 3986.567745] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Ubuntu-1.8.2-1ubuntu1 04/01/2014
> [ 3986.567746] Call Trace:
> ......
> [ 3986.567808]  drm_dp_aux_register_devnode+0xdc/0x140 [drm_kms_helper]
> ......
> [ 3986.569081] kobject_add_internal failed for drm_dp_aux_dev with -EEXIST, don't try to register things with the same name in the same directory.
> 
> Reproduce sequences:
> 1.modprobe amdgpu
> 2.modprobe -r amdgpu
> 3.modprobe amdgpu
> 
> Root cause:
> When unload driver, it don't unregister aux.
> 
> Signed-off-by: Emily Deng <Emily.Deng at amd.com>
> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h               |  1 +
>   drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c      | 18 +++++++++++++++++-
>   .../drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c    |  6 +++++-
>   3 files changed, 23 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
> index e48fd35..720955b 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_mode.h
> @@ -525,6 +525,7 @@ enum amdgpu_connector_dither {
>   struct amdgpu_dm_dp_aux {
>   	struct drm_dp_aux aux;
>   	struct ddc_service *ddc_service;
> +	bool has_aux;
>   };
>   
>   struct amdgpu_i2c_adapter {
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> index 8fe1685..de369ae 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c
> @@ -3760,6 +3760,16 @@ int amdgpu_dm_connector_atomic_get_property(struct drm_connector *connector,
>   	return ret;
>   }
>   
> +static void amdgpu_dm_connector_unregister(struct drm_connector *connector)
> +{
> +	struct amdgpu_dm_connector *amdgpu_dm_connector = to_amdgpu_dm_connector(connector);
> +
> +	if (amdgpu_dm_connector->dm_dp_aux.has_aux) {
> +		drm_dp_aux_unregister(&amdgpu_dm_connector->dm_dp_aux.aux);
> +		amdgpu_dm_connector->dm_dp_aux.has_aux = false;
> +	}
> +}

This is a good catch, but I'm pretty sure we don't need the has_aux 
state here for this.

You should be able to call drm_dp_aux_unregister regardless of whether 
drm_dp_aux_register succeeded or not.

Nicholas Kazlauskas

> +
>   static void amdgpu_dm_connector_destroy(struct drm_connector *connector)
>   {
>   	struct amdgpu_dm_connector *aconnector = to_amdgpu_dm_connector(connector);
> @@ -3788,6 +3798,11 @@ static void amdgpu_dm_connector_destroy(struct drm_connector *connector)
>   	drm_dp_cec_unregister_connector(&aconnector->dm_dp_aux.aux);
>   	drm_connector_unregister(connector);
>   	drm_connector_cleanup(connector);
> +	if (aconnector->i2c) {
> +		i2c_del_adapter(&aconnector->i2c->base);
> +		kfree(aconnector->i2c);
> +	}
> +
>   	kfree(connector);
>   }
>   
> @@ -3846,7 +3861,8 @@ static const struct drm_connector_funcs amdgpu_dm_connector_funcs = {
>   	.atomic_duplicate_state = amdgpu_dm_connector_atomic_duplicate_state,
>   	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
>   	.atomic_set_property = amdgpu_dm_connector_atomic_set_property,
> -	.atomic_get_property = amdgpu_dm_connector_atomic_get_property
> +	.atomic_get_property = amdgpu_dm_connector_atomic_get_property,
> +	.early_unregister = amdgpu_dm_connector_unregister
>   };
>   
>   static int get_modes(struct drm_connector *connector)
> diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> index 6e205ee..190e92c 100644
> --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_mst_types.c
> @@ -387,12 +387,16 @@ static const struct drm_dp_mst_topology_cbs dm_mst_cbs = {
>   void amdgpu_dm_initialize_dp_connector(struct amdgpu_display_manager *dm,
>   				       struct amdgpu_dm_connector *aconnector)
>   {
> +	int ret;
>   	aconnector->dm_dp_aux.aux.name = "dmdc";
>   	aconnector->dm_dp_aux.aux.dev = dm->adev->dev;
>   	aconnector->dm_dp_aux.aux.transfer = dm_dp_aux_transfer;
>   	aconnector->dm_dp_aux.ddc_service = aconnector->dc_link->ddc;
>   
> -	drm_dp_aux_register(&aconnector->dm_dp_aux.aux);
> +	ret = drm_dp_aux_register(&aconnector->dm_dp_aux.aux);
> +	if (!ret)
> +		aconnector->dm_dp_aux.has_aux = true;
> +
>   	drm_dp_cec_register_connector(&aconnector->dm_dp_aux.aux,
>   				      aconnector->base.name, dm->adev->dev);
>   	aconnector->mst_mgr.cbs = &dm_mst_cbs;
>