| Message ID | 20200806153650.3883530-1-thierry.reding@gmail.com |
|---|---|
| State | Accepted, archived |
| Headers | show |
| Series | of: platform: Destroy child devices symmetrically | expand |
| Context | Check | Description |
|---|---|---|
| robh/checkpatch | success |
On Thu, 06 Aug 2020 17:36:50 +0200, Thierry Reding wrote: > From: Thierry Reding <treding@nvidia.com> > > Iterate over child devices in reverse when unpopulating a platform > device to make this step symmetrical with the population step. This > fixes an issue in the Tegra DRM driver where upon module unload the > DPAUX controller tries to unregister an I2C controller but will end > up waiting indefinitely because one of the SOR devices is keeping a > reference to it. Since the SOR devices are instantiated after the > DPAUX devices, they would only be removed (and hence release their > reference to the I2C controller) after the DPAUX devices have been > removed. > > While destroying the child devices in reverse order helps in this > situation, it isn't fully safe to do so either. An even better way > would be for the child devices to be reordered to match the probe > order, which would work irrespective of the instantiation order. > > However, reordering by probe order would be fairly complicated and > doesn't fix any known issues, so we'll go with the simpler fix for > now. > > Signed-off-by: Thierry Reding <treding@nvidia.com> > --- > drivers/of/platform.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > Applied, thanks!
diff --git a/drivers/of/platform.c b/drivers/of/platform.c index 071f04da32c8..b557a0fcd4ba 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -590,7 +590,7 @@ EXPORT_SYMBOL_GPL(of_platform_device_destroy); void of_platform_depopulate(struct device *parent) { if (parent->of_node && of_node_check_flag(parent->of_node, OF_POPULATED_BUS)) { - device_for_each_child(parent, NULL, of_platform_device_destroy); + device_for_each_child_reverse(parent, NULL, of_platform_device_destroy); of_node_clear_flag(parent->of_node, OF_POPULATED_BUS); } }