[PATCH v7 0/5] drm: small cleanups and improvements

[PATCH v7 0/5] drm: small cleanups and improvements

[Luca Ceresoli]

This series collects some minor improvements and fixes previously part of
[0], hence the "v7" version number.

All of these patches already have some Review/Ack tags.

[0] https://lore.kernel.org/dri-devel/20250206-hotplug-drm-bridge-v6-0-9d6f2c9c3058@bootlin.com/

Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---
Luca Ceresoli (5):
      drm/debugfs: fix printk format for bridge index
      drm: of: drm_of_find_panel_or_bridge: move misplaced comment
      drm/bridge: panel: use drm_bridge_is_panel() instead of open code
      drm/bridge: panel: drm_panel_bridge_remove: warn when called on non-panel bridge
      drm/bridge: panel: forbid initializing a panel with unknown connector type

 drivers/gpu/drm/bridge/panel.c | 4 +++-
 drivers/gpu/drm/drm_debugfs.c  | 2 +-
 drivers/gpu/drm/drm_of.c       | 2 +-
 drivers/gpu/drm/drm_panel.c    | 5 ++++-
 4 files changed, 9 insertions(+), 4 deletions(-)
---
base-commit: a64dcfb451e254085a7daee5fe51bf22959d52d3
change-id: 20250214-drm-assorted-cleanups-dd6d8e1b4a8a

Best regards,
-- 
Luca Ceresoli <luca.ceresoli@bootlin.com>

[PATCH v7 1/5] drm/debugfs: fix printk format for bridge index

[Luca Ceresoli]

idx is an unsigned int, use %u for printk-style strings.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---

Changes in v7: none

This patch was added in v6.
---
 drivers/gpu/drm/drm_debugfs.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
index 536409a35df406dae0dd7ade01b3f3d1e2c9e8f9..6b2178864c7ee12db9aa1f562e106b2f604439f8 100644
--- a/drivers/gpu/drm/drm_debugfs.c
+++ b/drivers/gpu/drm/drm_debugfs.c
@@ -748,7 +748,7 @@ static int bridges_show(struct seq_file *m, void *data)
 	unsigned int idx = 0;
 
 	drm_for_each_bridge_in_chain(encoder, bridge) {
-		drm_printf(&p, "bridge[%d]: %ps\n", idx++, bridge->funcs);
+		drm_printf(&p, "bridge[%u]: %ps\n", idx++, bridge->funcs);
 		drm_printf(&p, "\ttype: [%d] %s\n",
 			   bridge->type,
 			   drm_get_connector_type_name(bridge->type));

-- 
2.48.1

[PATCH v7 2/5] drm: of: drm_of_find_panel_or_bridge: move misplaced comment

[Luca Ceresoli]

This comment is misleading as it refers to one of the inner if() branches
only, not the whole outer if(). Move it to the branch it refers to.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---

Changes in v7: none

This patch was added in v6.
---
 drivers/gpu/drm/drm_of.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_of.c b/drivers/gpu/drm/drm_of.c
index 5530919e0ba05f7ce1806730b292319f36e905ed..d0183dea770308e77f05da364ffe087d53f3be36 100644
--- a/drivers/gpu/drm/drm_of.c
+++ b/drivers/gpu/drm/drm_of.c
@@ -268,9 +268,9 @@ int drm_of_find_panel_or_bridge(const struct device_node *np,
 			*panel = NULL;
 	}
 
-	/* No panel found yet, check for a bridge next. */
 	if (bridge) {
 		if (ret) {
+			/* No panel found yet, check for a bridge next. */
 			*bridge = of_drm_find_bridge(remote);
 			if (*bridge)
 				ret = 0;

-- 
2.48.1

[PATCH v7 3/5] drm/bridge: panel: use drm_bridge_is_panel() instead of open code

[Luca Ceresoli]

drm_panel_bridge_remove() reads bridge->funcs to find out whether this is a
panel bridge or another kind of bridge. drm_bridge_is_panel() is made
exactly for that, so use it.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---

Changes in v7: none

This patch was added in v6.
---
 drivers/gpu/drm/bridge/panel.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
index 6e88339dec0f5faee690b7c53e8dcd0f1ee2281c..0c5db13b11dcb90ee88b9932b91aa05fc48d59bd 100644
--- a/drivers/gpu/drm/bridge/panel.c
+++ b/drivers/gpu/drm/bridge/panel.c
@@ -322,7 +322,7 @@ void drm_panel_bridge_remove(struct drm_bridge *bridge)
 	if (!bridge)
 		return;
 
-	if (bridge->funcs != &panel_bridge_bridge_funcs)
+	if (!drm_bridge_is_panel(bridge))
 		return;
 
 	panel_bridge = drm_bridge_to_panel_bridge(bridge);

-- 
2.48.1

[PATCH v7 4/5] drm/bridge: panel: drm_panel_bridge_remove: warn when called on non-panel bridge

[Luca Ceresoli]

This function is for panel_bridge instances only. The silent return when
invoked on other bridges might hide actual errors, so avoid them to go
unnoticed.

Reviewed-by: Maxime Ripard <mripard@kernel.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---

Changes in v7: none

This patch was added in v6.
---
 drivers/gpu/drm/bridge/panel.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/bridge/panel.c b/drivers/gpu/drm/bridge/panel.c
index 0c5db13b11dcb90ee88b9932b91aa05fc48d59bd..c57036b06493a6922e2cae38bcd1733930ff0073 100644
--- a/drivers/gpu/drm/bridge/panel.c
+++ b/drivers/gpu/drm/bridge/panel.c
@@ -322,8 +322,10 @@ void drm_panel_bridge_remove(struct drm_bridge *bridge)
 	if (!bridge)
 		return;
 
-	if (!drm_bridge_is_panel(bridge))
+	if (!drm_bridge_is_panel(bridge)) {
+		drm_warn(bridge->dev, "%s: called on non-panel bridge!\n", __func__);
 		return;
+	}
 
 	panel_bridge = drm_bridge_to_panel_bridge(bridge);
 

-- 
2.48.1

[PATCH v7 5/5] drm/bridge: panel: forbid initializing a panel with unknown connector type

[Luca Ceresoli]

Having an DRM_MODE_CONNECTOR_Unknown connector type is considered bad, and
drm_panel_bridge_add_typed() and derivatives are deprecated for this.

drm_panel_init() won't prevent initializing a panel with a
DRM_MODE_CONNECTOR_Unknown connector type. Luckily there are no in-tree
users doing it, so take this as an opportinuty to document a valid
connector type must be passed.

Returning an error if this rule is violated is not possible because
drm_panel_init() is a void function. Add at least a warning to make any
violations noticeable, especially to non-upstream drivers.

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Luca Ceresoli <luca.ceresoli@bootlin.com>
---

Changed in v7:
- fix typo in commit message
- rebased on v6 (applies to drm_panel, not bridge/panel.c)

This patch was added in v6.
---
 drivers/gpu/drm/drm_panel.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_panel.c b/drivers/gpu/drm/drm_panel.c
index 9940e96d35e302080c32b49154bbf19a51c0665e..c627e42a7ce70459f50eb5095fffc806ca45dabf 100644
--- a/drivers/gpu/drm/drm_panel.c
+++ b/drivers/gpu/drm/drm_panel.c
@@ -50,7 +50,7 @@ static LIST_HEAD(panel_list);
  * @dev: parent device of the panel
  * @funcs: panel operations
  * @connector_type: the connector type (DRM_MODE_CONNECTOR_*) corresponding to
- *	the panel interface
+ *	the panel interface (must NOT be DRM_MODE_CONNECTOR_Unknown)
  *
  * Initialize the panel structure for subsequent registration with
  * drm_panel_add().
@@ -58,6 +58,9 @@ static LIST_HEAD(panel_list);
 void drm_panel_init(struct drm_panel *panel, struct device *dev,
 		    const struct drm_panel_funcs *funcs, int connector_type)
 {
+	if (connector_type == DRM_MODE_CONNECTOR_Unknown)
+		DRM_WARN("%s: %s: a valid connector type is required!\n", __func__, dev_name(dev));
+
 	INIT_LIST_HEAD(&panel->list);
 	INIT_LIST_HEAD(&panel->followers);
 	mutex_init(&panel->follower_lock);

-- 
2.48.1

Re: [PATCH v7 0/5] drm: small cleanups and improvements

[Robert Foss]

On Fri, 14 Feb 2025 13:57:39 +0100, Luca Ceresoli wrote:
> This series collects some minor improvements and fixes previously part of
> [0], hence the "v7" version number.
> 
> All of these patches already have some Review/Ack tags.
> 
> [0] https://lore.kernel.org/dri-devel/20250206-hotplug-drm-bridge-v6-0-9d6f2c9c3058@bootlin.com/
> 
> [...]

Applied, thanks!

[1/5] drm/debugfs: fix printk format for bridge index
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/72443c730b7a
[2/5] drm: of: drm_of_find_panel_or_bridge: move misplaced comment
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/9d60cf4e8cf7
[3/5] drm/bridge: panel: use drm_bridge_is_panel() instead of open code
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/cc46371e3d32
[4/5] drm/bridge: panel: drm_panel_bridge_remove: warn when called on non-panel bridge
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/77053ef7207a
[5/5] drm/bridge: panel: forbid initializing a panel with unknown connector type
      https://gitlab.freedesktop.org/drm/misc/kernel/-/commit/b296955b3a74



Rob