On 2/10/21 7:49 AM, Dave Stevenson wrote: > Hi Marc. > > On Wed, 10 Feb 2021 at 15:30, Marc Zyngier <maz@xxxxxxxxxx> wrote: >> >> Hi Maxime, >> >> On 2021-02-10 14:40, Maxime Ripard wrote: >>> 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@xxxxxxxxxx> 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? >> >> No, not really. That's because the chained handler is actually an >> interrupt flow, and not a normal handler. IRQF_SHARED acts at the wrong >> level for that. >> >> I can see two possibilities: >> >> - the l2-intc gets turned into a normal handler, and does the demux >> from there. Horrible stuff. >> >> - the i2c controller gets parented to the l2c-int as a fake interrupt, >> and gets called from there. Horrible stuff. >> >> Pick your poison... :-/ > > Thanks for the info. > > Option 3 - remove l2-intc and drop back to polling the i2c-brcmstb > blocks (which the driver supports anyway). > HDMI I2C generally isn't heavily used once displays are connected, so > I'd be OK with that. > > (We can keep the l2-intc that handles CEC and HPD as that is on a > unique GIC interrupt). Agreed, Maxime or Nicolas do you want me to send a revert of this patch? -- Florian _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
