Since the kconfig symbol of DRM_PANEL_BRIDGE is only adding
bridge/panel.o to drm_kms_helper object, we need to select
DRM_KMS_HELPER to make sure the file is actually getting built.
Otherwise with certain defconfigs e.g. devm_drm_of_get_bridge will not
be properly available:
aarch64-linux-gnu-ld: drivers/phy/qualcomm/phy-qcom-qmp-combo.o: in function `qmp_combo_bridge_attach':
drivers/phy/qualcomm/phy-qcom-qmp-combo.c:3204:(.text+0x8f4): undefined reference to `devm_drm_of_get_bridge'
Signed-off-by: Luca Weiss <luca.weiss@xxxxxxxxxxxxx>
---
I can see "depends on DRM_KMS_HELPER" was removed with commit
3c3384050d68 ("drm: Don't make DRM_PANEL_BRIDGE dependent on DRM_KMS_HELPERS")
I'm not too familiar with Kconfig but it feels more correct if
PHY_QCOM_QMP_COMBO selects DRM_PANEL_BRIDGE that that's enough; and it
doesn't also has to explicitly select DRM_KMS_HELPER because of how the
objects are built in the Makefile.
Alternatively solution to this patch could be adjusting this line in
include/drm/drm_bridge.h:
-#if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL_BRIDGE)
+#if defined(CONFIG_OF) && defined(CONFIG_DRM_PANEL_BRIDGE) && defined(CONFIG_DRM_KMS_HELPER)
struct drm_bridge *devm_drm_of_get_bridge(struct device *dev, struct device_node *node,
u32 port, u32 endpoint);
.. and then selecting DRM_KMS_HELPER for PHY_QCOM_QMP_COMBO.
But I think the solution in this patch is better. Let me know what you
think.
---
drivers/gpu/drm/bridge/Kconfig | 1 +
1 file changed, 1 insertion(+)
diff --git a/drivers/gpu/drm/bridge/Kconfig b/drivers/gpu/drm/bridge/Kconfig
index ac9ec5073619..ae782b427829 100644
--- a/drivers/gpu/drm/bridge/Kconfig
+++ b/drivers/gpu/drm/bridge/Kconfig
@@ -8,6 +8,7 @@ config DRM_BRIDGE
config DRM_PANEL_BRIDGE
def_bool y
depends on DRM_BRIDGE
+ select DRM_KMS_HELPER
select DRM_PANEL
help
DRM bridge wrapper of DRM panels
---
base-commit: b9c3a1fa6fb324e691a03cf124b79f4842e65d76
change-id: 20240111-drm-panel-bridge-fixup-5c2977fb969f
Best regards,
--
Luca Weiss <luca.weiss@xxxxxxxxxxxxx>
