Re: [PATCH v2 59/59] drm/connector: Remove reset

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] drm/connector: premature removal of reset hook breaks unconverted drivers
--

commit 86331e69eb719274bf362ebe2870d757866546bb
Author: Maxime Ripard <mripard@kernel.org>

drm/connector: Remove reset

This commit removes the reset callback from struct drm_connector_funcs and
drops the calls to it in drm_mode_config_reset(), drmm_connector_hdmi_init(),
drmm_connector_hdmi_ini2(), and panel_bridge_attach().

[ ... ]

> diff --git a/drivers/gpu/drm/drm_mode_config.c b/drivers/gpu/drm/drm_mode_config.c
> index 48a56f23dadbb..c1e993a78702e 100644
> --- a/drivers/gpu/drm/drm_mode_config.c
> +++ b/drivers/gpu/drm/drm_mode_config.c
> @@ -315,9 +315,7 @@ void drm_mode_config_reset(struct drm_device *dev)
>  
>  	drm_connector_list_iter_begin(dev, &conn_iter);
>  	drm_for_each_connector_iter(connector, &conn_iter) {
> -		if (connector->funcs->reset)
> -			connector->funcs->reset(connector);
> -		else if (connector->funcs->atomic_create_state)
> +		if (connector->funcs->atomic_create_state)
>  			drm_mode_config_connector_reset_with_create_state(connector);
>  	}
>  	drm_connector_list_iter_end(&conn_iter);

[ ... ]

> diff --git a/include/drm/drm_connector.h b/include/drm/drm_connector.h
> index a87cd13d0a45f..f656ed8324d37 100644
> --- a/include/drm/drm_connector.h
> +++ b/include/drm/drm_connector.h
> @@ -1658,15 +1658,6 @@ struct drm_connector_funcs {
>  	 */
>  	int (*dpms)(struct drm_connector *connector, int mode);
>  
> -	/**
> -	 * @reset:
> -	 *
> -	 * Reset connector hardware and software state to off. This function isn't
> -	 * called by the core directly, only through drm_mode_config_reset().
> -	 * It's not a helper hook only for historical reasons.
> -	 */
> -	void (*reset)(struct drm_connector *connector);
> -
>  	/**
>  	 * @detect:
>  	 *

[Severity: High]
Are all in-tree users of struct drm_connector_funcs.reset converted to
atomic_create_state before removing this callback?

Removing reset from struct drm_connector_funcs in include/drm/drm_connector.h
and dropping the connector->funcs->reset(connector) call from
drm_mode_config_reset() in drivers/gpu/drm/drm_mode_config.c appears to break
the build for 26 struct drm_connector_funcs definitions across 25 files that
still initialize .reset and do not implement .atomic_create_state.

Specifically, several drivers still wire up custom reset callbacks:

drivers/gpu/drm/arm/malidp_mw.c:
static const struct drm_connector_funcs malidp_mw_connector_funcs = {
	.reset = malidp_mw_connector_reset,

drivers/gpu/drm/renesas/rcar-du/rcar_du_writeback.c:
static const struct drm_connector_funcs rcar_du_wb_conn_funcs = {
	.reset = rcar_du_wb_conn_reset,

drivers/gpu/drm/vmwgfx/vmwgfx_ldu.c (and vmw_sou_connector_funcs in
drivers/gpu/drm/vmwgfx/vmwgfx_scrn.c, vmw_stdu_connector_funcs in
drivers/gpu/drm/vmwgfx/vmwgfx_stdu.c):
static const struct drm_connector_funcs vmw_legacy_connector_funcs = {
	.dpms = vmw_du_connector_dpms,
	.detect = vmw_du_connector_detect,
	.fill_modes = drm_helper_probe_single_connector_modes,
	.destroy = vmw_ldu_connector_destroy,
	.reset = vmw_du_connector_reset,

In addition, the sysfb helper macro and several other drivers, bridges, and
KUnit tests still initialize .reset to drm_atomic_helper_connector_reset:

drivers/gpu/drm/sysfb/drm_sysfb_helper.h (used by simpledrm.c, efidrm.c,
ofdrm.c, vesadrm.c, and corebootdrm.c):
#define DRM_SYSFB_CONNECTOR_FUNCS \
	.reset = drm_atomic_helper_connector_reset, \
	.fill_modes = drm_helper_probe_single_connector_modes, \
	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state, \
	.atomic_destroy_state = drm_atomic_helper_connector_destroy_state

Other unconverted struct drm_connector_funcs definitions include:
- komeda_wb_connector_funcs in
  drivers/gpu/drm/arm/display/komeda/komeda_wb_connector.c
- lt8912_connector_funcs in drivers/gpu/drm/bridge/lontium-lt8912b.c
- ge_b850v3_lvds_connector_funcs in
  drivers/gpu/drm/bridge/megachips-stdpxxxx-ge-b850v3-fw.c
- sii902x_connector_funcs in drivers/gpu/drm/bridge/sii902x.c
- simple_bridge_con_funcs in drivers/gpu/drm/bridge/simple-bridge.c
- hv_drm_connector_funcs in drivers/gpu/drm/hyperv/hyperv_drm_modeset.c
- imx_tve_connector_funcs in drivers/gpu/drm/imx/ipuv3/imx-tve.c
- dpu_wb_conn_funcs in drivers/gpu/drm/msm/disp/dpu1/dpu_writeback.c
- ssd130x_connector_funcs in drivers/gpu/drm/solomon/ssd130x.c
- lvds_conn_funcs in drivers/gpu/drm/stm/lvds.c
- appletbdrm_connector_funcs in drivers/gpu/drm/tiny/appletbdrm.c
- vc4_txp_connector_funcs in drivers/gpu/drm/vc4/vc4_txp.c
- vc4_dummy_connector_funcs in drivers/gpu/drm/vc4/tests/vc4_mock_output.c
- dm_test_audio_connector_funcs in
  drivers/gpu/drm/amd/display/amdgpu_dm/tests/amdgpu_dm_audio_test.c (along
  with amdgpu_dm_backlight_test.c, amdgpu_dm_crc_test.c,
  amdgpu_dm_helpers_test.c, amdgpu_dm_irq_test.c, amdgpu_dm_mst_types_test.c,
  and amdgpu_dm_wb_test.c)

Beyond failing to compile when any of these drivers or tests are enabled,
wouldn't drm_mode_config_reset() also skip state allocation for these
connectors because they do not implement atomic_create_state, leaving
connector->state uninitialized or unreset?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20261022-drm-no-more-connector-reset-v2-0-0b7e4e85b1e8@kernel.org?part=59