If our compatible string has "simple-bus" at the end of it then the
system will handle probing our children for us. Doing this has a few
advantages:
1. If we defer we don't have to keep probing / removing our children
which should speed up boot. The system just probes them once.
2. It fixes a problem where we could get into a big loop where we'd
have:
- msm_pdev_probe() is called.
- msm_pdev_probe() registers drivers. Registering drivers kicks
off processing of probe deferrals.
- component_master_add_with_match() could return -EPROBE_DEFER.
making msm_pdev_probe() return -EPROBE_DEFER.
- When msm_pdev_probe() returned the processing of probe deferrals
happens.
- Loop back to the start.
Signed-off-by: Douglas Anderson <dianders@xxxxxxxxxxxx>
---
drivers/gpu/drm/msm/msm_drv.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 78b09fde9e29..f7c6ef147095 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -1208,10 +1208,18 @@ static int add_display_components(struct device *dev,
if (of_device_is_compatible(dev->of_node, "qcom,mdss") ||
of_device_is_compatible(dev->of_node, "qcom,sdm845-mdss") ||
of_device_is_compatible(dev->of_node, "qcom,sc7180-mdss")) {
- ret = devm_of_platform_populate(dev);
- if (ret) {
- DRM_DEV_ERROR(dev, "failed to populate children devices\n");
- return ret;
+ /*
+ * Old device tree files didn't include "simple-bus"
+ * in their compatible string so we had to manually pouplate
+ * our children. When existing device trees are fixed this
+ * can be removed.
+ */
+ if (!of_device_is_compatible(dev->of_node, "simple-bus")) {
+ ret = devm_of_platform_populate(dev);
+ if (ret) {
+ DRM_DEV_ERROR(dev, "failed to populate children devices\n");
+ return ret;
+ }
}
mdp_dev = device_find_child(dev, NULL, compare_name_mdp);
--
2.27.0.383.g050319c2ae-goog
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