On Thu, Apr 25, 2019 at 02:24:18PM +0800, junxiao.ch...@intel.com wrote: > From: Junxiao Chang <junxiao.ch...@intel.com> > > When platform device is deleted or there is error in adding > device, platform device resources should be released. Currently > API release_resource is used to release platform device resources. > However, this API releases not only platform resource itself but > also its child resources. It might release resources which are > still in use. Calling remove_resource only releases current > resource itself, not resource tree, it moves its child resources > to up level.
But shouldn't the parent device not get removed until all of the children are removed? What is causing this "inversion" to happen? > > For example, platform device 1 and device 2 are registered, then only > device 1 is unregistered in below code: > > ... > // Register platform test device 1, resource 0xfed1a000 ~ 0xfed1afff > pdev1 = platform_device_register_full(&pdevinfo1); > > // Register platform test device 2, resource 0xfed1a200 ~ 0xfed1a2ff > pdev2 = platform_device_register_full(&pdevinfo2); > > // Now platform device 2 resource should be device 1 resource's child > > // Unregister device 1 only > platform_device_unregister(pdev1); > ... Don't do that. :) You created this mess of platform devices, so you need to keep track of them. > Platform device 2 resource will be released as well because its > parent resource(device 1's resource) is released, this is not expected. > If using API remove_resource, device 2 resource will not be released. > > This change fixed an intel pmc platform device resource issue when > intel pmc ipc kernel module is inserted/removed for twice. Why not fix that kernel module instead? It seems like that is the real problem here, not a driver core issue. thanks, greg k-h
