6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Jani Nikula <jani.nikula@xxxxxxxxx> [ Upstream commit 7af03e688792293ba33149fb8df619a8dff90e80 ] The .get_modes() callback is supposed to return the number of modes, never a negative error code. If a negative value is returned, it'll just be interpreted as a negative count, and added to previous calculations. Document the rules, but handle the negative values gracefully with an error message. Cc: stable@xxxxxxxxxxxxxxx Acked-by: Thomas Zimmermann <tzimmermann@xxxxxxx> Link: https://patchwork.freedesktop.org/patch/msgid/50208c866facc33226a3c77b82bb96aeef8ef310.1709913674.git.jani.nikula@xxxxxxxxx Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/gpu/drm/drm_probe_helper.c | 7 +++++++ include/drm/drm_modeset_helper_vtables.h | 3 ++- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c index 3b968ad187cf3..52dbaf74fe164 100644 --- a/drivers/gpu/drm/drm_probe_helper.c +++ b/drivers/gpu/drm/drm_probe_helper.c @@ -362,6 +362,13 @@ static int drm_helper_probe_get_modes(struct drm_connector *connector) count = connector_funcs->get_modes(connector); + /* The .get_modes() callback should not return negative values. */ + if (count < 0) { + drm_err(connector->dev, ".get_modes() returned %pe\n", + ERR_PTR(count)); + count = 0; + } + /* * Fallback for when DDC probe failed in drm_get_edid() and thus skipped * override/firmware EDID. diff --git a/include/drm/drm_modeset_helper_vtables.h b/include/drm/drm_modeset_helper_vtables.h index fafa70ac1337f..6f19cf5c210e5 100644 --- a/include/drm/drm_modeset_helper_vtables.h +++ b/include/drm/drm_modeset_helper_vtables.h @@ -896,7 +896,8 @@ struct drm_connector_helper_funcs { * * RETURNS: * - * The number of modes added by calling drm_mode_probed_add(). + * The number of modes added by calling drm_mode_probed_add(). Return 0 + * on failures (no modes) instead of negative error codes. */ int (*get_modes)(struct drm_connector *connector); -- 2.43.0
