From mboxrd@z Thu Jan  1 00:00:00 1970
From: Duc Dang <dhdang@apm.com>
Subject: Defining polarity and trigger mode for static interrupts in _PRT
Date: Wed, 24 Aug 2016 04:06:13 -0700
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To: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>, Rafael Wysocki <rafael@kernel.org>
Cc: linux-pci@vger.kernel.org, linux-acpi@vger.kernel.org, Marc Zyngier <marc.zyngier@arm.com>, patches <patches@apm.com>

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Hi Lorenzo, Rafael,

ACPI 6.1 spec does not specify how to set interrupt polarity and
trigger mode in _PRT when the interrupts are static (hardwired to
specific interrupt inputs in interrupt controller). In current
acpi_pci_irq_enable (drivers/acpi/pci_irq.c) implementation, by
default the trigger mode is set to LEVEL_SENSITIVE, polarity is set to
ACTIVE_LOW. This default setting won't work for ARM64 GICv2, GICv2m,
GICv3 controllers and will cause failures in PCIe AER, PME services
(on X-Gene platforms).

Is there any way to specify polarity and trigger mode for static
interrupts in _PRT? If not, can we introduce a _weak_ hook to specify
default polarity and trigger mode for for ARM64 PCIe INTx in
drivers/acpi/pci_irq.c?

Regards,
Duc Dang.