Re: [PATCH] drm/stm: ltdc: Silence -EPROBE_DEFER till bridge attached

[yannick Fertre]

Hi Jagan,

thanks for the patch.

Tested-by: Yannick Fertre <yannick.fer...@foss.st.com>


On 7/4/21 3:59 PM, Jagan Teki wrote:

As dw-mipi-dsi supported all possible ways to find the DSI
devices. It can take multiple iterations for ltdc to find
all components attached to the DSI bridge.

The current ltdc driver failed to find the endpoint as
it returned -EINVAL for the first iteration itself. This leads
to following error:

[    3.099289] [drm:ltdc_load] *ERROR* init encoder endpoint 0

So, check the return value and cleanup the encoder only if it's
not -EPROBE_DEFER. This make all components in the attached DSI
bridge found properly.

Signed-off-by: Jagan Teki <ja...@amarulasolutions.com>
---
  drivers/gpu/drm/stm/ltdc.c | 8 +++++---
  1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/stm/ltdc.c b/drivers/gpu/drm/stm/ltdc.c
index 08b71248044d..95e983d3ffb5 100644
--- a/drivers/gpu/drm/stm/ltdc.c
+++ b/drivers/gpu/drm/stm/ltdc.c
@@ -1122,8 +1122,9 @@ static int ltdc_encoder_init(struct drm_device *ddev, 
struct drm_bridge *bridge)

ret = drm_bridge_attach(encoder, bridge, NULL, 0);

        if (ret) {
-               drm_encoder_cleanup(encoder);
-               return -EINVAL;
+               if (ret != -EPROBE_DEFER)
+                       drm_encoder_cleanup(encoder);
+               return ret;
        }

DRM_DEBUG_DRIVER("Bridge encoder:%d created\n", encoder->base.id);

@@ -1266,7 +1267,8 @@ int ltdc_load(struct drm_device *ddev)
                if (bridge) {
                        ret = ltdc_encoder_init(ddev, bridge);
                        if (ret) {
-                               DRM_ERROR("init encoder endpoint %d\n", i);
+                               if (ret != -EPROBE_DEFER)
+                                       DRM_ERROR("init encoder endpoint %d\n", 
i);
                                goto err;
                        }
                }