[PATCH v4] ACPI: AGDI: Add interrupt signaling mode support

[Charles Mirabile]

Hi All—

On Mon, Nov 10, 2025 at 07:38:17AM +0000, Kazuhiro Abe (Fujitsu) wrote:
> Hi Will,
> 
> > Hi Will,
> > 
> > > [You don't often get email from will at kernel.org. Learn why this is
> > > important at https://aka.ms/LearnAboutSenderIdentification ]
> > >
> > > On Mon, Oct 20, 2025 at 09:23:05PM +0800, Hanjun Guo wrote:
> > > > On 2025/10/17 15:39, Kazuhiro Abe wrote:
> > > > > AGDI has two types of signaling modes: SDEI and interrupt.
> > > > > Currently, the AGDI driver only supports SDEI.
> > > > > Therefore, add support for interrupt signaling mode The interrupt
> > > > > vector is retrieved from the AGDI table, and call panic function
> > > > > when an interrupt occurs.
> > > > >
> > > > > Reviewed-by: Ilkka Koskinen <ilkka at os.amperecomputing.com>
> > > > > Signed-off-by: Kazuhiro Abe <fj1078ii at aa.jp.fujitsu.com>
> > > > > ---
> > > > > Hanjun, I have addressed all your comments.
> > > > > Please review them.
> > > > >
> > > > > v3->v4
> > > > >   - Add a comment to the flags member.
> > > > >   - Fix agdi_interrupt_probe.
> > > > >   - Fix agdi_interrupt_remove.
> > > > >   - Add space in struct initializsation.
> > > > >   - Delete curly braces.
> > > >
> > > > Looks good to me,
> > > >
> > > > Acked-by: Hanjun Guo <guohanjun at huawei.com>
> > >
> > > I wasn't cc'd on the original patch but I couldn't figure out why it
> > > uses IRQF_NO_AUTOEN when requesting the irq given that the first thing
> > > it does is enable it.
> > 
> > I misunderstood the usage of request_irq and enable_irq.
> > Since there's no need to separate them, I will remove IRQF_NO_AUTOEN and the
> > enable_irq call, and send v5.
> 
> I found out when calling request_nmi, removing IRQF_NO_AUTOEN results in an error (-EINVAL).
> Therefore, I would like to keep IRQF_NO_AUTOEN specified.
> If you have any comments on this version, please let me know.

Could it be that this is just a bug in `request_nmi`? I see the following:

if (!desc || (irq_settings_can_autoenable(desc) &&
    !(irqflags & IRQF_NO_AUTOEN)) ||
    !irq_settings_can_request(desc) ||
    WARN_ON(irq_settings_is_per_cpu_devid(desc)) ||
    !irq_supports_nmi(desc))
	return -EINVAL;

Perhaps there is just a missing `!` before `irq_settings_can_autoenable`.

As far as I can tell it has always been wrong - git blame points me to the
original commit where that code was introduced:

b525903c254da ("genirq: Provide basic NMI management for interrupt lines")

I looked and the only two callers are using `IRQF_NO_AUTOEN` so I guess it
just hasn't been noticed yet.

Happy to send a patch to fix it.

> 
> Best Regards,
> Kazuhiro Abe
> 
> > 
> > Best Regards,
> > Kazuhiro Abe
> > 
> > >
> > > Will

Best—Charlie