x86-power-control

[Vijay Khemka]

On 10/17/19, 4:27 PM, "openbmc on behalf of Bills, Jason M" <openbmc-bounces+vijaykhemka=fb.com at lists.ozlabs.org on behalf of jason.m.bills at linux.intel.com> wrote:

    
    
    On 10/17/2019 3:32 PM, Vijay Khemka wrote:
    > 
    > On 10/17/19, 9:03 AM, "openbmc on behalf of Bills, Jason M" <openbmc-bounces+vijaykhemka=fb.com at lists.ozlabs.org on behalf of jason.m.bills at linux.intel.com> wrote:
    > 
    >      Hi Vijay
    >      
    >      On 10/16/2019 6:13 PM, Vijay Khemka wrote:
    >      > One more question on code, I see following code requires powerButtonMask
    >      > to be set before aquiring GPIO line. Please let me know who sets this
    >      > powerButtonMask to true. I know this is related to GPIO passthrough but
    >      > still couldn’t understand where in code it gets set until someone call
    >      > set-property of dbus.
    >      
    >      powerButtonMask is a gpiod::line object that returns true if it
    >      references a GPIO line and false otherwise.
    > 
    > I understood code but my point here is there will not be any
    > gpiod::line object if powerButtonMask is defined as false. And
    > initially it is defined as false means tehre will not be any line
    > object created until someone sets it to true. And I don't see it
    > any way to set it true other than set-property through dbus.
    
    That's correct.  Masking the power button is something that is done by 
    some component outside of power-control.
    
    For example, we currently use it with the Set Front Panel Button Enables 
    IPMI command to enable/disable the power button.  So, it is only masked 
    when requested.
So to use x-86-power-control, either we need to have IPMI command to enable
this or some other daemon has to set this property. Can we have this feature 
optional. I guess this is a prt og GPIO passthrough.
    
    The actual "POWER_OUT" line for power-control is not permanently 
    created, but is asserted using temporary calls like this one:
    setGPIOOutputForMs("POWER_OUT", 0, powerPulseTimeMs);

This function will not run power on/off sequence until button mask is set. It
Will only set GPIO value which is not enough for powering on/off.
    
    https://github.com/openbmc/x86-power-control/blob/master/power-control-x86/src/power_control.cpp#L946
    
    >      
    >      >
    >      > power_control::powerButtonIface->register_property(
    >      >
    >      > "ButtonMasked", false, [](constboolrequested, bool& current) {
    >      >
    >      > if(requested)
    >      >
    >      > {
    >      >
    >      > if(power_control::powerButtonMask)
    >      >
    >      > {
    >      This will return if powerButtonMask already references a GPIO.
    >      
    >      >
    >      > return1;
    >      >
    >      > }
    >      >
    >      > if(!power_control::setGPIOOutput(
    >      >
    >      > "POWER_OUT", 1, power_control::powerButtonMask))
    >      Otherwise, this will request the "POWER_OUT" GPIO and assign it to
    >      powerButtonMask (which will make it return true).
    >      
    >      >
    >      > {
    >      >
    >      > throwstd::runtime_error("Failed to request GPIO");
    >      >
    >      > return0;
    >      >
    >      > }
    >      >
    >      > std::cerr << "Power Button Masked.\n";
    >      >
    >      > }
    >      >
    >      > else
    >      >
    >      > {
    >      >
    >      > if(!power_control::powerButtonMask)
    >      >
    >      > {
    >      This will return if powerButtonMask does not reference a GPIO line.
    >      
    >      >
    >      > return1;
    >      >
    >      > }
    >      >
    >      > std::cerr << "Power Button Un-masked\n";
    >      >
    >      > power_control::powerButtonMask.reset();
    >      Otherwise this will reset powerButtonMask to release the "POWER_OUT"
    >      GPIO (which will make it return false).
    >      
    >      >
    >      > }
    >      >
    >      > Regards
    >      >
    >      > -Vijay
    >      >
    >      
    >