Re: [PATCH 2/8] drm/panel: do not return negative error codes from drm_panel_get_modes()

2024-03-11 Thread Neil Armstrong 

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 
Cc: Jessica Zhang 
Cc: Sam Ravnborg 
Cc: sta...@vger.kernel.org
Signed-off-by: Jani Nikula 
---
  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

Re: [PATCH 2/8] drm/panel: do not return negative error codes from drm_panel_get_modes()

2024-03-08 Thread Jessica Zhang 




On 3/8/2024 8:03 AM, 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 
Cc: Jessica Zhang 
Cc: Sam Ravnborg 
Cc: sta...@vger.kernel.org
Signed-off-by: Jani Nikula 
---
  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;


Hi Jani,

The change LGTM:

Reviewed-by: Jessica Zhang 

Thanks,

Jessica Zhang


+   }
+
+   return 0;
  }
  EXPORT_SYMBOL(drm_panel_get_modes);
  
--

2.39.2

[PATCH 2/8] drm/panel: do not return negative error codes from drm_panel_get_modes()

2024-03-08 Thread Jani Nikula 
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 
Cc: Jessica Zhang 
Cc: Sam Ravnborg 
Cc: sta...@vger.kernel.org
Signed-off-by: Jani Nikula 
---
 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);
 
-- 
2.39.2