The Rockchip RGB CRTC output driver attempts to avoid probing Rockchip subdrivers to see if they're a connected panel or bridge. However part of its checks assumes that if no OF platform device is found then it can't be a valid bridge or panel. This causes issues with I2C controlled bridges that have not yet been registered to the point they can be found.
Change this to return EPROBE_DEFER instead of ENODEV and don't ignore such devices. The subsequent call to drm_of_find_panel_or_bridge() will return EPROBE_DEFER as well if there's actually a valid device we should wait for. Signed-off-by: Jonathan McDowell <[email protected]> --- drivers/gpu/drm/rockchip/rockchip_drm_drv.c | 8 ++++++-- drivers/gpu/drm/rockchip/rockchip_rgb.c | 7 ++++--- 2 files changed, 10 insertions(+), 5 deletions(-) diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c index 212bd87c0c4a..b0d63a566501 100644 --- a/drivers/gpu/drm/rockchip/rockchip_drm_drv.c +++ b/drivers/gpu/drm/rockchip/rockchip_drm_drv.c @@ -270,11 +270,15 @@ int rockchip_drm_endpoint_is_subdriver(struct device_node *ep) if (!node) return -ENODEV; - /* status disabled will prevent creation of platform-devices */ + /* + * status disabled will prevent creation of platform-devices, + * but equally we can't rely on the driver having been registered + * yet (e.g. I2C bridges). + */ pdev = of_find_device_by_node(node); of_node_put(node); if (!pdev) - return -ENODEV; + return -EPROBE_DEFER; /* * All rockchip subdrivers have probed at this point, so diff --git a/drivers/gpu/drm/rockchip/rockchip_rgb.c b/drivers/gpu/drm/rockchip/rockchip_rgb.c index c079714477d8..989595087397 100644 --- a/drivers/gpu/drm/rockchip/rockchip_rgb.c +++ b/drivers/gpu/drm/rockchip/rockchip_rgb.c @@ -77,7 +77,7 @@ struct rockchip_rgb *rockchip_rgb_init(struct device *dev, struct drm_encoder *encoder; struct device_node *port, *endpoint; u32 endpoint_id; - int ret = 0, child_count = 0; + int subret, ret = 0, child_count = 0; struct drm_panel *panel; struct drm_bridge *bridge; @@ -96,8 +96,9 @@ struct rockchip_rgb *rockchip_rgb_init(struct device *dev, if (of_property_read_u32(endpoint, "reg", &endpoint_id)) endpoint_id = 0; - /* if subdriver (> 0) or error case (< 0), ignore entry */ - if (rockchip_drm_endpoint_is_subdriver(endpoint) != 0) + /* if subdriver (> 0) or non-defer error case (< 0), ignore entry */ + subret = rockchip_drm_endpoint_is_subdriver(endpoint); + if (subret != 0 && subret != -EPROBE_DEFER) continue; child_count++; -- 2.20.1
