Re: [PATCH RFC 0/4] irqchip: qcom: add support for PDC interrupt controller

From: Sudeep Holla
Date: Tue Jan 23 2018 - 13:15:24 EST


Hi Lina,

On Tue, Jan 23, 2018 at 5:56 PM, Lina Iyer <ilina@xxxxxxxxxxxxxx> wrote:
> On newer Qualcomm Techonologies Inc's SoCs like the SDM845, the GIC is in a
> power domain that can be powered off when not needed. Interrupts that need to
> be sensed even when the GIC is powered off, are routed through an interrupt
> controller in an always-on domain called the Power Domain Controller a.k.a PDC.
> This series adds support for the PDC's interrupt controller.
>

Sorry for the basic questions:

1. Will the GIC be powered off in any other state other than System suspend ?

2. Why this needs to be done in Linux, why can't it be transparent and hidden
in the firmware doing the actual GIC power down ? I assume Linux is not
powering down the GIC.

3. I see some bits that enable secure interrupts in one of the patch.
Is that even
safe to allow Linux to enable some secure interrupts in PDC ?

--
Regards,
Sudeep