On Tue, 21 Feb 2006 kaustav.majumdar@xxxxxxxxx wrote: > Hi all, > > We are facing an issue regarding power management of a PCMCIA based USB > Host Controller driver. > > When we are issuing the command "echo -n "3" > > /sys/class/pcmcia-socket/pcmcia-socket1/device/power/state" from the > command line (the PC Card was in socket 1), we received the "PM_SUSPEND" > event in the event handler of the PCMCIA client driver. On getting that, > inside the client driver, we are releasing the configuration by calling > pcmcia_release_configuration. > > When we debugged the code, we noted that though we are getting suspend > event in the pcmcia client driver, the suspend entry points in the hc > driver are not being called. > > So from that I think a mechanism is needed to communicate this event to > the hc driver. One possible solution is to set a variable in the PCMCIA > client driver on suspend and polling that variable from the hc driver. > > Pl. suggest a better solution. Looking forward to your suggestions. Suspend messages sent via sysfs are not propagated down to child devices and drivers. Your userspace program has to make sure to suspend all the children before trying to suspend a device. That means suspending all the descendants (interfaces and devices) of the host controller, then the host controller itself, then the PCMCIA client driver. The same is true of resume messages sent via sysfs. They don't get propagated either, so again your userspace program must resume all the children in the device tree. Alan Stern
