Re: [PATCH v2 14/15] ARM: dts: bcm2711: Add the BSC interrupt controller

Maxime Ripard
2021-02-10T14:42:17Z

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Hi Dave,

On Tue, Feb 09, 2021 at 09:49:05AM +0000, Dave Stevenson wrote:
> On Mon, 11 Jan 2021 at 14:23, Maxime Ripard <maxime@cerno.tech> wrote:
> >
> > The BSC controllers used for the HDMI DDC have an interrupt controller
> > shared between both instances. Let's add it to avoid polling.
>
> This seems to have unintended side effects.
> GIC interrupt 117 is shared between the standard I2C controllers
> (i2c-bcm2835) and the l2-intc block handling the HDMI I2C interrupts.
>
> Whilst i2c-bcm2835 requests the interrupt with IRQF_SHARED, that
> doesn't appear to be an option for l2-intc registering as an interrupt
> controller. i2c-bcm2835 therefore loses out and fails to register for
> the interrupt.
>
> Is there an equivalent flag that an interrupt controller can add to
> say that the parent interrupt is shared? Is that even supported?

Indeed, it looks like setting an equivalent to IRQF_SHARED would be the
solution, but I couldn't find anything that would allow us to in the
irqchip code.

Marc, Thomas, is it something that is allowed?

Thanks!
Maxime

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