Re: [PATCH V3 1/4] ACPI / PCI: fix LPIC irq model default PCI IRQ polarity

[Jianmin Lv]

Ok, thanks, I'll improve them as your suggestion.

On 2022/10/20 上午12:05, Bjorn Helgaas wrote:
> In the subject and the commit log below, figure out whether you want
> to use "irq" or "IRQ" and do it consistently.  I vote for "IRQ".  Also
> consider subject lines for the other patches.  Stuff like this is
> trivial, but it's an excuse for whoever will handle this (not me in
> this case) to put it off.  I also add "()" after function names for
> clarity.
>
> On Sun, Oct 09, 2022 at 02:44:28PM +0800, Jianmin Lv wrote:
> > On LoongArch ACPI based systems, the irq trigger type of PCI devices
> > is high level, so high level triggered type is required to pass
> > to acpi_register_gsi when create irq mapping for PCI devices.
>
> This isn't worded quite right.  The trigger type of PCI devices
> doesn't change just because you plug them into a LoongArch system
> instead of an x86 system.  The comment in the code reads better: The
> IRQs are active low from the perspective of PCI, but are inverted
> before the interrupt controller.
>
> Including a reference here to the spec that mentions this inversion
> would help a lot.
>
> s/when create mapping/when creating mappings/
>
> > Signed-off-by: Jianmin Lv <lvjianmin@xxxxxxxxxxx>
> > ---
> >   drivers/acpi/pci_irq.c | 6 ++++--
> >   1 file changed, 4 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/acpi/pci_irq.c b/drivers/acpi/pci_irq.c
> > index 08e15774fb9f..ff30ceca2203 100644
> > --- a/drivers/acpi/pci_irq.c
> > +++ b/drivers/acpi/pci_irq.c
> > @@ -387,13 +387,15 @@ int acpi_pci_irq_enable(struct pci_dev *dev)
> >   	u8 pin;
> >   	int triggering = ACPI_LEVEL_SENSITIVE;
> >   	/*
> > -	 * On ARM systems with the GIC interrupt model, level interrupts
> > +	 * On ARM systems with the GIC interrupt model, or LoongArch
> > +	 * systems with the LPIC interrupt model, level interrupts
> >   	 * are always polarity high by specification; PCI legacy
> >   	 * IRQs lines are inverted before reaching the interrupt
> >   	 * controller and must therefore be considered active high
> >   	 * as default.
> >   	 */
> > -	int polarity = acpi_irq_model == ACPI_IRQ_MODEL_GIC ?
> > +	int polarity = acpi_irq_model == ACPI_IRQ_MODEL_GIC ||
> > +		       acpi_irq_model == ACPI_IRQ_MODEL_LPIC ?
> >   				      ACPI_ACTIVE_HIGH : ACPI_ACTIVE_LOW;
> >   	char *link = NULL;
> >   	char link_desc[16];
> > --
> > 2.31.1