From 7af03e688792293ba33149fb8df619a8dff90e80 Mon Sep 17 00:00:00 2001 From: Jani Nikula Date: Fri, 8 Mar 2024 18:03:39 +0200 Subject: drm/probe-helper: warn about negative .get_modes() 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@vger.kernel.org Acked-by: Thomas Zimmermann Link: https://patchwork.freedesktop.org/patch/msgid/50208c866facc33226a3c77b82bb96aeef8ef310.1709913674.git.jani.nikula@intel.com Signed-off-by: Jani Nikula --- drivers/gpu/drm/drm_probe_helper.c | 7 +++++++ 1 file changed, 7 insertions(+) (limited to 'drivers/gpu/drm/drm_probe_helper.c') diff --git a/drivers/gpu/drm/drm_probe_helper.c b/drivers/gpu/drm/drm_probe_helper.c index 19ecb749704b..75f84753f6ee 100644 --- a/drivers/gpu/drm/drm_probe_helper.c +++ b/drivers/gpu/drm/drm_probe_helper.c @@ -422,6 +422,13 @@ 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. -- cgit v1.2.3-70-g09d2