availability of interrupts during bootup process

John Baldwin jhb at freebsd.org
Wed Sep 5 13:54:59 UTC 2012


On Tuesday, September 04, 2012 9:30:08 pm Warner Losh wrote:
> 
> On Sep 4, 2012, at 10:05 AM, John Baldwin wrote:
> 
> > On Sunday, September 02, 2012 5:31:21 pm Aleksander Dutkowski wrote:
> >> hello!
> >> 
> >> I have PMIC (TWL4030) module connected to the SoC (ARM/OMAP3) via i2c 
> > (iicbus).
> >> Current solution is that i2c_attach calls bus_generic_attach(dev);
> >> which calls my pmic probe/attach functions, but main configuration of
> >> PMIC in done after drivers setup by config_intrhook.
> >> But I need it to be configured during device attaching, because usb
> >> ehci driver depends on it.
> >> Is it possbile? I've tried it but it hangs on waiting for i2c
> >> interrupt, but someone told me, that interrupts are available during
> >> bootup for some time.
> > 
> > No, interrupts do not work during bootup.  If you can poll your hardware
> > you could use polling until interrupts are enabled (using 'if (cold)' to
> > check for the boot time before interrupts are enabled).
> 
> Are interrupts off, or ithreads not scheduled?  I thought I had some stuff
> working that needed interrupts, but didn't need scheduling..  Am I nuts?

No, that's correct.  Filters will work, just not scheduling.

-- 
John Baldwin


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