1. Isn't it the kernel which is finally initiating a low power sleep state? So, I added it in kernel/power/main.c where the kernel does all the suspend related activities. 2. To answer your second question, we really can't guarantee. But even if you take Windows Vista (sorry linux enthusiasts for referring windows here) or any other non-UNIX operating systems (which has this power event notification), they really do not guarantee it. But, it is an era-of-tera and the user space applications can do some minimal work like saving the app's last state in a .tmp file or so (like firefox if closed in an unclean way) to restore their state. I have tested it over some applications of my own and they seem to execute a significant piece of code-like writing to a file when they go to low power state. Really appreciate your comment. Thanks. Thanks, Sankara Narayanan V. -----Original Message----- From: Oliver Neukum [mailto:oliver@xxxxxxxxxx] Sent: Thursday, July 05, 2007 5:38 PM To: linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx Cc: V, Sankara Narayanan Subject: Re: Power event notification patch Am Donnerstag, 5. Juli 2007 schrieb V, Sankara Narayanan: > Here is a simple patch for power event notification to user-space > applications. Basically, what it does is notify the user-space > applications that the system is going to a low power state > (Suspend-to-RAM and Suspend-to-Disk) and resume from that state. This is > useful for the user-space applications to do some significant action > when the system goes to the low power state (like saving an unsaved > file). The user-space objects can form a netlink socket and listen to > these events. It is done through a kobject-netlink socket. For this I > have used the kobject_uevent system call, posting the notification to > user space with standby, hibernate and resume in the action parameter of > the kobject_uevent call (mapped to KOBJ_S3, KOBJ_S4 and KOBJ_RESUME > enums). Appreciate your comments on the patch. Why does this need to be done in kernel space? How do you want to make sure user space has enough time to act on a notification? Regards Oliver _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
