On 08/03/2024 17:03, Jani Nikula wrote:
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@xxxxxxxxxx>
Cc: Jessica Zhang <quic_jesszhan@xxxxxxxxxxx>
Cc: Sam Ravnborg <sam@xxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
---
drivers/gpu/drm/drm_panel.c | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index e814020bbcd3..cfbe020de54e 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -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);
Reviewed-by: Neil Armstrong <neil.armstrong@xxxxxxxxxx>
