diff options
| -rw-r--r-- | Documentation/PCI/boot-interrupts.rst | 34 |
1 files changed, 19 insertions, 15 deletions
diff --git a/Documentation/PCI/boot-interrupts.rst b/Documentation/PCI/boot-interrupts.rst index d078ef3eb192..2ec70121bfca 100644 --- a/Documentation/PCI/boot-interrupts.rst +++ b/Documentation/PCI/boot-interrupts.rst @@ -32,12 +32,13 @@ interrupt goes unhandled over time, they are tracked by the Linux kernel as Spurious Interrupts. The IRQ will be disabled by the Linux kernel after it reaches a specific count with the error "nobody cared". This disabled IRQ now prevents valid usage by an existing interrupt which may happen to share -the IRQ line. +the IRQ line:: irq 19: nobody cared (try booting with the "irqpoll" option) CPU: 0 PID: 2988 Comm: irq/34-nipalk Tainted: 4.14.87-rt49-02410-g4a640ec-dirty #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 @@ -85,15 +86,18 @@ Mitigations The mitigations take the form of PCI quirks. The preference has been to first identify and make use of a means to disable the routing to the PCH. In such a case a quirk to disable boot interrupt generation can be -added.[1] +added. [1]_ - Intel® 6300ESB I/O Controller Hub +Intel® 6300ESB I/O Controller Hub Alternate Base Address Register: BIE: Boot Interrupt Enable - 0 = Boot interrupt is enabled. - 1 = Boot interrupt is disabled. - Intel® Sandy Bridge through Sky Lake based Xeon servers: + == =========================== + 0 Boot interrupt is enabled. + 1 Boot interrupt is disabled. + == =========================== + +Intel® Sandy Bridge through Sky Lake based Xeon servers: Coherent Interface Protocol Interrupt Control dis_intx_route2pch/dis_intx_route2ich/dis_intx_route2dmi2: When this bit is set. Local INTx messages received from the @@ -109,12 +113,12 @@ line by default. Therefore, on chipsets where this INTx routing cannot be disabled, the Linux kernel will reroute the valid interrupt to its legacy interrupt. This redirection of the handler will prevent the occurrence of the spurious interrupt detection which would ordinarily disable the IRQ -line due to excessive unhandled counts.[2] +line due to excessive unhandled counts. [2]_ The config option X86_REROUTE_FOR_BROKEN_BOOT_IRQS exists to enable (or disable) the redirection of the interrupt handler to the PCH interrupt line. The option can be overridden by either pci=ioapicreroute or -pci=noioapicreroute.[3] +pci=noioapicreroute. [3]_ More Documentation @@ -127,19 +131,19 @@ into the evolution of its handling with chipsets. Example of disabling of the boot interrupt ------------------------------------------ -Intel® 6300ESB I/O Controller Hub (Document # 300641-004US) + - Intel® 6300ESB I/O Controller Hub (Document # 300641-004US) 5.7.3 Boot Interrupt https://www.intel.com/content/dam/doc/datasheet/6300esb-io-controller-hub-datasheet.pdf -Intel® Xeon® Processor E5-1600/2400/2600/4600 v3 Product Families -Datasheet - Volume 2: Registers (Document # 330784-003) + - Intel® Xeon® Processor E5-1600/2400/2600/4600 v3 Product Families + Datasheet - Volume 2: Registers (Document # 330784-003) 6.6.41 cipintrc Coherent Interface Protocol Interrupt Control https://www.intel.com/content/dam/www/public/us/en/documents/datasheets/xeon-e5-v3-datasheet-vol-2.pdf Example of handler rerouting ---------------------------- -Intel® 6700PXH 64-bit PCI Hub (Document # 302628) + - Intel® 6700PXH 64-bit PCI Hub (Document # 302628) 2.15.2 PCI Express Legacy INTx Support and Boot Interrupt https://www.intel.com/content/dam/doc/datasheet/6700pxh-64-bit-pci-hub-datasheet.pdf @@ -150,6 +154,6 @@ Cheers, Sean V Kelley sean.v.kelley@linux.intel.com -[1] https://lore.kernel.org/r/12131949181903-git-send-email-sassmann@suse.de/ -[2] https://lore.kernel.org/r/12131949182094-git-send-email-sassmann@suse.de/ -[3] https://lore.kernel.org/r/487C8EA7.6020205@suse.de/ +.. [1] https://lore.kernel.org/r/12131949181903-git-send-email-sassmann@suse.de/ +.. [2] https://lore.kernel.org/r/12131949182094-git-send-email-sassmann@suse.de/ +.. [3] https://lore.kernel.org/r/487C8EA7.6020205@suse.de/ |