[PATCH] drm/imx: select DRM_DISPLAY_HELPER as needed

[PATCH] drm/imx: select DRM_DISPLAY_HELPER as needed

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

CONFIG_DRM_BRIDGE_CONNECTOR is a bool option that turns on features of
the display helpers, which are in a module controlled by the (tristate)
CONFIG_DRM_DISPLAY_HELPER. If the display helpers are in a loadable
module, a built-in driver trying to use the bridge connectors fails
to link:

x86_64-linux-ld: drivers/gpu/drm/imx/ipuv3/parallel-display.o: in function `imx_pd_bind':
parallel-display.c:(.text+0xcd): undefined reference to `drm_bridge_connector_init'
x86_64-linux-ld: drivers/gpu/drm/imx/ipuv3/imx-ldb.o: in function `imx_ldb_bind':
imx-ldb.c:(.text+0x224): undefined reference to `drm_bridge_connector_init'

Select the DRM_BRIDGE_CONNECTOR symbol as well, to ensure it's built-in
if anything needs it.

Fixes: f94b9707a1c9 ("drm/imx: parallel-display: switch to imx_legacy_bridge / drm_bridge_connector")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/gpu/drm/imx/ipuv3/Kconfig | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/imx/ipuv3/Kconfig b/drivers/gpu/drm/imx/ipuv3/Kconfig
index acaf25089001..1c3825a86380 100644
--- a/drivers/gpu/drm/imx/ipuv3/Kconfig
+++ b/drivers/gpu/drm/imx/ipuv3/Kconfig
@@ -13,6 +13,7 @@ config DRM_IMX
 config DRM_IMX_PARALLEL_DISPLAY
 	tristate "Support for parallel displays"
 	depends on DRM_IMX
+	select DRM_DISPLAY_HELPER
 	select DRM_BRIDGE
 	select DRM_BRIDGE_CONNECTOR
 	select DRM_IMX_LEGACY_BRIDGE
@@ -33,6 +34,7 @@ config DRM_IMX_LDB
 	depends on DRM_IMX
 	depends on COMMON_CLK
 	select MFD_SYSCON
+	select DRM_DISPLAY_HELPER
 	select DRM_BRIDGE
 	select DRM_BRIDGE_CONNECTOR
 	select DRM_PANEL_BRIDGE
-- 
2.39.5

Re: [PATCH] drm/imx: select DRM_DISPLAY_HELPER as needed

[Dmitry Baryshkov]

On 04/12/2025 11:46, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> CONFIG_DRM_BRIDGE_CONNECTOR is a bool option that turns on features of
> the display helpers, which are in a module controlled by the (tristate)
> CONFIG_DRM_DISPLAY_HELPER. If the display helpers are in a loadable
> module, a built-in driver trying to use the bridge connectors fails
> to link:
> 
> x86_64-linux-ld: drivers/gpu/drm/imx/ipuv3/parallel-display.o: in function `imx_pd_bind':
> parallel-display.c:(.text+0xcd): undefined reference to `drm_bridge_connector_init'
> x86_64-linux-ld: drivers/gpu/drm/imx/ipuv3/imx-ldb.o: in function `imx_ldb_bind':
> imx-ldb.c:(.text+0x224): undefined reference to `drm_bridge_connector_init'
> 
> Select the DRM_BRIDGE_CONNECTOR symbol as well, to ensure it's built-in
> if anything needs it.
> 
> Fixes: f94b9707a1c9 ("drm/imx: parallel-display: switch to imx_legacy_bridge / drm_bridge_connector")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   drivers/gpu/drm/imx/ipuv3/Kconfig | 2 ++
>   1 file changed, 2 insertions(+)

Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>

-- 
With best wishes
Dmitry

Re: [PATCH] drm/imx: select DRM_DISPLAY_HELPER as needed

[Lalaev, Andrei]

Hi,

Gentle ping.

I noticed that another patch [1] selects DRM_DISPLAY_HELPER for DRM_IMX_PARALLEL_DISPLAY, but not for DRM_IMX_LDB.

[1] - https://lore.kernel.org/lkml/20260121102607.4087362-1-martin.kepplinger-novakovic@ginzinger.com/

Best regards,
Andrei Lalaev