On Sun, Oct 09, 2016 at 08:28:19PM +0300, Grazvydas Ignotas wrote:
> 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>
would be nice to also split things up on the register side, for symmetry.
Just as one small step towards demidlayering amdgpu.
-Daniel
> ---
> 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
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
