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PCI: Add boot interrupt quirk mechanism for Xeon chipsets
The following was observed by Kar Hin Ong with RT patchset: Backtrace: irq 19: nobody cared (try booting with the "irqpoll" option) CPU: 0 PID: 3329 Comm: irq/34-nipalk Tainted:4.14.87-rt49 friendlyarm#1 Hardware name: National Instruments NI PXIe-8880/NI PXIe-8880, BIOS 2.1.5f1 01/09/2020 Call Trace: <IRQ> ? dump_stack+0x46/0x5e ? __report_bad_irq+0x2e/0xb0 ? note_interrupt+0x242/0x290 ? nNIKAL100_memoryRead16+0x8/0x10 [nikal] ? handle_irq_event_percpu+0x55/0x70 ? handle_irq_event+0x4f/0x80 ? handle_fasteoi_irq+0x81/0x180 ? handle_irq+0x1c/0x30 ? do_IRQ+0x41/0xd0 ? common_interrupt+0x84/0x84 </IRQ> ... handlers: [<ffffffffb3297200>] irq_default_primary_handler threaded [<ffffffffb3669180>] usb_hcd_irq Disabling IRQ rockchip-linux#19 The problem being that this device is triggering boot interrupts due to threaded interrupt handling and masking of the IO-APIC. These boot interrupts are then forwarded on to the legacy PCH's PIRQ lines where there is no handler present for the device. Whenever a PCI device fires interrupt (INTx) to Pin 20 of IOAPIC 2 (GSI 44), the kernel receives two interrupts: 1. Interrupt from Pin 20 of IOAPIC 2 -> Expected 2. Interrupt from Pin 19 of IOAPIC 1 -> UNEXPECTED Quirks for disabling boot interrupts (preferred) or rerouting the handler exist but do not address these Xeon chipsets' mechanism: https://lore.kernel.org/lkml/[email protected]/ Add a new mechanism via PCI CFG for those chipsets supporting CIPINTRC register's dis_intx_rout2ich bit. Link: https://lore.kernel.org/r/[email protected] Reported-by: Kar Hin Ong <[email protected]> Tested-by: Kar Hin Ong <[email protected]> Signed-off-by: Sean V Kelley <[email protected]> Signed-off-by: Bjorn Helgaas <[email protected]> Reviewed-by: Thomas Gleixner <[email protected]> Cc: [email protected]
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