#3919 HIGH Never A: Power off via Geode, not EC side effect

[Zarro Boogs per Child]

#3919: Power off via Geode, not EC side effect
-------------------------------+--------------------------------------------
 Reporter:  wmb at firmworks.com  |       Owner:  dilinger      
     Type:  defect             |      Status:  new           
 Priority:  high               |   Milestone:  Never Assigned
Component:  kernel             |     Version:                
 Keywords:                     |    Verified:  0             
-------------------------------+--------------------------------------------
 The current implementation of olpc_power_off() in arch/i386/kernel/olpc.c
 works by turning the EC microcontroller off then back on, depending on the
 assumption that the EC will turn off the main CPU during its reset
 sequence.  That assumption is not guaranteed, and may in fact change soon.

 A better way is to tell the Geode to turn itself off, using the following
 code, which should go in olpc-pm.c, not olpc.c

 {{{
 olpc_power_off(void)
 {
         /* Enable all of these controls with 0 delay */
         outl(0x40000000, pms_base + PM_SCLK);
         outl(0x40000000, pms_base + PM_IN_SLPCTL);
         outl(0x40000000, pms_base + PM_WKXD);
         outl(0x40000000, pms_base + PM_WKD);

         /* Clear status bits (possibly unnecessary) */
         outl(0x0002ffff, pms_base  + PM_SSC);
         outl(0xffffffff, acpi_base + PM_GPE0_STS);

         /* Write SLP_EN bit to start the machinery */
         outl(0x00002000, acpi_base + PM1_CNT1);
 }
 }}}

-- 
Ticket URL: <https://dev.laptop.org/ticket/3919>
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