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drm/bridge: panel: Check device dependency before managing device link

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Some panel devices already depend on DRM device, like the panel in
arch/arm/boot/dts/st/ste-ux500-samsung-skomer.dts, because DRM device is
the ancestor of those panel devices.  device_link_add() would fail by
returning a NULL pointer for those panel devices because of the existing
dependency.  So, check the dependency by calling device_is_dependent()
before adding or deleting device link between panel device and DRM device
so that the link is managed only for independent panel devices.

Fixes: 887878014534 ("drm/bridge: panel: Fix device link for DRM_BRIDGE_ATTACH_NO_CONNECTOR")
Fixes: 199cf07ebd2b ("drm/bridge: panel: Add a device link between drm device and panel device")
Reported-by: Linus Walleij <linus.walleij@linaro.org>
Closes: https://lore.kernel.org/lkml/CACRpkdaGzXD6HbiX7mVUNJAJtMEPG00Pp6+nJ1P0JrfJ-ArMvQ@mail.gmail.com/T/
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231123032615.3760488-1-victor.liu@nxp.com
This commit is contained in:
Liu Ying 2023-11-23 11:26:15 +08:00 committed by Linus Walleij
parent ab93edb2f9
commit 39d5b6a64a
1 changed files with 18 additions and 9 deletions
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27
drivers/gpu/drm/bridge/panel.c
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@ -23,6 +23,7 @@ struct panel_bridge {
struct drm_panel *panel;
struct device_link *link;
u32 connector_type;
bool is_independent;
};
static inline struct panel_bridge *
@ -67,12 +68,17 @@ static int panel_bridge_attach(struct drm_bridge *bridge,
struct drm_device *drm_dev = bridge->dev;
int ret;
panel_bridge->link = device_link_add(drm_dev->dev, panel->dev,
DL_FLAG_STATELESS);
if (!panel_bridge->link) {
DRM_ERROR("Failed to add device link between %s and %s\n",
dev_name(drm_dev->dev), dev_name(panel->dev));
return -EINVAL;
panel_bridge->is_independent = !device_is_dependent(drm_dev->dev,
panel->dev);
if (panel_bridge->is_independent) {
panel_bridge->link = device_link_add(drm_dev->dev, panel->dev,
DL_FLAG_STATELESS);
if (!panel_bridge->link) {
DRM_ERROR("Failed to add device link between %s and %s\n",
dev_name(drm_dev->dev), dev_name(panel->dev));
return -EINVAL;
}
}
if (flags & DRM_BRIDGE_ATTACH_NO_CONNECTOR)
@ -80,7 +86,8 @@ static int panel_bridge_attach(struct drm_bridge *bridge,
if (!bridge->encoder) {
DRM_ERROR("Missing encoder\n");
device_link_del(panel_bridge->link);
if (panel_bridge->is_independent)
device_link_del(panel_bridge->link);
return -ENODEV;
}
@ -92,7 +99,8 @@ static int panel_bridge_attach(struct drm_bridge *bridge,
panel_bridge->connector_type);
if (ret) {
DRM_ERROR("Failed to initialize connector\n");
device_link_del(panel_bridge->link);
if (panel_bridge->is_independent)
device_link_del(panel_bridge->link);
return ret;
}
@ -115,7 +123,8 @@ static void panel_bridge_detach(struct drm_bridge *bridge)
struct panel_bridge *panel_bridge = drm_bridge_to_panel_bridge(bridge);
struct drm_connector *connector = &panel_bridge->connector;
device_link_del(panel_bridge->link);
if (panel_bridge->is_independent)
device_link_del(panel_bridge->link);
/*
* Cleanup the connector if we know it was initialized.