Hi, Marc,
On Thu, Sep 10, 2020 at 6:08 PM Marc Zyngier <maz@xxxxxxxxxx> wrote:
>
> On 2020-09-09 05:09, Huacai Chen wrote:
> > Reserve legacy LPC irqs (0~15) to avoid spurious interrupts.
>
> How can they be spurious? Why are they enabled the first place?
>
> This looks like you are papering over a much bigger issue.
The spurious interrupts are probably occurred after kdump and the irq
number is in legacy LPC ranges. I think this is because the old kernel
doesn't (and it can't) disable devices properly so there are stale
interrupts in the kdump case.
Huacai
>
> M.
> >
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Huacai Chen <chenhc@xxxxxxxxxx>
> > ---
> > drivers/irqchip/irq-loongson-pch-pic.c | 19 ++++++++++++++++++-
> > 1 file changed, 18 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/irqchip/irq-loongson-pch-pic.c
> > b/drivers/irqchip/irq-loongson-pch-pic.c
> > index 9bf6b9a..9f6719c 100644
> > --- a/drivers/irqchip/irq-loongson-pch-pic.c
> > +++ b/drivers/irqchip/irq-loongson-pch-pic.c
> > @@ -35,6 +35,7 @@
> >
> > struct pch_pic {
> > void __iomem *base;
> > + struct irq_domain *lpc_domain;
> > struct irq_domain *pic_domain;
> > u32 ht_vec_base;
> > raw_spinlock_t pic_lock;
> > @@ -184,9 +185,9 @@ static void pch_pic_reset(struct pch_pic *priv)
> > static int pch_pic_of_init(struct device_node *node,
> > struct device_node *parent)
> > {
> > + int i, base, err;
> > struct pch_pic *priv;
> > struct irq_domain *parent_domain;
> > - int err;
> >
> > priv = kzalloc(sizeof(*priv), GFP_KERNEL);
> > if (!priv)
> > @@ -213,6 +214,22 @@ static int pch_pic_of_init(struct device_node
> > *node,
> > goto iounmap_base;
> > }
> >
> > + base = irq_alloc_descs(-1, 0, NR_IRQS_LEGACY, 0);
> > + if (base < 0) {
> > + pr_err("Failed to allocate LPC IRQ numbers\n");
> > + goto iounmap_base;
> > + }
> > +
> > + priv->lpc_domain = irq_domain_add_legacy(node, NR_IRQS_LEGACY, 0, 0,
> > + &irq_domain_simple_ops, NULL);
> > + if (!priv->lpc_domain) {
> > + pr_err("Failed to add irqdomain for LPC controller");
> > + goto iounmap_base;
> > + }
> > +
> > + for (i = 0; i < NR_IRQS_LEGACY; i++)
> > + irq_set_chip_and_handler(i, &dummy_irq_chip, handle_simple_irq);
> > +
> > priv->pic_domain = irq_domain_create_hierarchy(parent_domain, 0,
> > PIC_COUNT,
> > of_node_to_fwnode(node),
>
> --
> Jazz is not dead. It just smells funny...
