Commit fc4e9772 authored Mar 08, 2024 by Jani Nikula

drm/panel: do not return negative error codes from drm_panel_get_modes()



None of the callers of drm_panel_get_modes() expect it to return
negative error codes. Either they propagate the return value in their
struct drm_connector_helper_funcs .get_modes() hook (which is also not
supposed to return negative codes), or add it to other counts leading to
bogus values.

On the other hand, many of the struct drm_panel_funcs .get_modes() hooks
do return negative error codes, so handle them gracefully instead of
propagating further.

Return 0 for no modes, whatever the reason.

Cc: Neil Armstrong <neil.armstrong@linaro.org>
Cc: Jessica Zhang <quic_jesszhan@quicinc.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: stable@vger.kernel.org
Reviewed-by: Neil Armstrong <neil.armstrong@linaro.org>
Reviewed-by: Jessica Zhang <quic_jesszhan@quicinc.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/79f559b72d8c493940417304e222a4b04dfa19c4.1709913674.git.jani.nikula@intel.com


Signed-off-by: Jani Nikula <jani.nikula@intel.com>

parent 7af03e68

drivers/gpu/drm/drm_panel.c

+11 −6

Original line number	Diff line number	Diff line
		@@ -274,19 +274,24 @@ EXPORT_SYMBOL(drm_panel_disable);
		* The modes probed from the panel are automatically added to the connector
		* that the panel is attached to.
		*
		* Return: The number of modes available from the panel on success or a
		* negative error code on failure.
		* Return: The number of modes available from the panel on success, or 0 on
		* failure (no modes).
		*/
		int drm_panel_get_modes(struct drm_panel *panel,
		struct drm_connector *connector)
		{
		if (!panel)
		return -EINVAL;
		return 0;

		if (panel->funcs && panel->funcs->get_modes)
		return panel->funcs->get_modes(panel, connector);
		if (panel->funcs && panel->funcs->get_modes) {
		int num;

		return -EOPNOTSUPP;
		num = panel->funcs->get_modes(panel, connector);
		if (num > 0)
		return num;
		}

		return 0;
		}
		EXPORT_SYMBOL(drm_panel_get_modes);