Re: [PATCH v14 11/18] irqchip: Add RISC-V incoming MSI controller early driver

Anup Patel
2024-02-23T09:53:11Z

On Fri, Feb 23, 2024 at 1:58 PM Thomas Gleixner <tglx@linutronix.de> wrote:
>
> On Thu, Feb 22 2024 at 15:09, Anup Patel wrote:
> > + /*
> > + * Setup cpuhp state (must be done after setting imsic_parent_irq)
> > + *
> > + * Don't disable per-CPU IMSIC file when CPU goes offline
> > + * because this affects IPI and the masking/unmasking of
> > + * virtual IPIs is done via generic IPI-Mux
> > + */
> > + cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "irqchip/riscv/imsic:starting",
> > + imsic_starting_cpu, imsic_dying_cpu);
>
> This is not really correct. IPIs should be working right away when a CPU
> comes online and on the unplug side until it really goes offline.
>
> So this wants to be in the starting range, i.e. between CPUHP_AP_OFFLINE
> and CPUHP_AP_ONLINE. No?

Yes, it has to be as early as possible but I was not sure about
introducing yet another driver specific CPUHP_AP_xyz state
considering CPUHP_AP_ONLINE_DYN worked fine.

Since you suggested, let me introduce
CPUHP_AP_IRQ_RISCV_IMSIC_STARTING in the next revision.

Regards,
Anup