Hi Jonathan,
Am Dienstag, 16. März 2021, 19:27:53 CET schrieb Jonathan McDowell:
> 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 <noodles@xxxxxxxx>
> ---
> 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;
In general, how does that relate to i2c-bridge-drivers, as
of_find_device_by_node supposedly only acts on platform-devices?
Also if that points to a disabled bridge (hdmi, etc) that would likely make
it probe-defer indefinitly, as that device will never become available?
Maybe we could do something like of_device_is_available() which checks
the status property of the node. So something like:
pdev = of_find_device_by_node(node);
if (!pdev) {
bool avail = of_device_is_available(node);
of_node_put(node);
/* if disabled
if (!avail)
return -ENODEV;
else
return -EPROBE_DEFER;
}
of_node_put(node);
Though I still do not understand how that should actually pick up on
i2c devices at all.
Heiko
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