On 3/3/07, Mitch Bradley <[EMAIL PROTECTED]> wrote:
The OLPC OS does not use the ACPI interface, nor does the OLPC firmware support it . The OS drivers perform the appropriate power management operations directly, with full knowledge of the behavior of the hardware on which they operate. The firmware exports a low-level suspend-to-RAM function in the form of a subroutine. The OS, after doing whatever driver work is necessary, calls that subroutine. The firmware then saves the core state and puts the hardware into a low-power state with RAM powered in self-refresh mode. Upon a wakeup event, the firmware restores the core state and returns from the subroutine. The current size of the firmware suspend/resume code is about 1K. It is written in assembly language, optimized to do its job as quickly as possible. We hope to be able to do "micro sleeps" so fast that the user will not realize that the system is sleeping. OLPC has special hardware features for retaining the image on the screen and for performing wireless mesh routing while the main processor is powered off.
Thank you very much for such a nice explanation. In the code i saw a lot of "magic" port numbers. Is there any documentation describing them (esp. ones not found in traditional PC). -- -------------------------------------------------------- Manish Regmi Volunteer OLPC Nepal _______________________________________________ Devel mailing list [email protected] http://mailman.laptop.org/mailman/listinfo/devel
