[PATCH] PCI/MSI: mvebu: Re-enable arch fallbacks

From: Domenico Andreoli <domenico.andreoli@linux.com>
To: Andrew Lunn <andrew@lunn.ch>,
	Gregory Clement <gregory.clement@bootlin.com>,
	Sebastian Hesselbarth <sebastian.hesselbarth@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH] PCI/MSI: mvebu: Re-enable arch fallbacks
Date: Wed, 16 Mar 2022 10:33:15 +0100	[thread overview]
Message-ID: <YjGu2zJo9hGGg/jZ@localhost> (raw)

From: Domenico Andreoli <domenico.andreoli@linux.com>

Since v5.10, my QNAP happily barks at boot as follows (5.17.0-rc8):

[    0.923811] ------------[ cut here ]------------
[    0.928458] WARNING: CPU: 0 PID: 1 at drivers/pci/msi/msi.h:17 pci_msi_setup_msi_irqs+0x54/0x6c
[    0.937219] Modules linked in:
[    0.940290] CPU: 0 PID: 1 Comm: swapper Not tainted 5.17.0-rc8-marvell #6
[    0.947117] Hardware name: Marvell Kirkwood (Flattened Device Tree)
[    0.953428]  unwind_backtrace from show_stack+0x10/0x14
[    0.958698]  show_stack from __warn+0xac/0xe4
[    0.963093]  __warn from warn_slowpath_fmt+0x68/0x80
[    0.968098]  warn_slowpath_fmt from pci_msi_setup_msi_irqs+0x54/0x6c
[    0.974499]  pci_msi_setup_msi_irqs from __pci_enable_msi_range+0x260/0x340
[    0.981509]  __pci_enable_msi_range from pci_alloc_irq_vectors_affinity+0xb8/0xf8
[    0.989043]  pci_alloc_irq_vectors_affinity from xhci_run+0x164/0x474
[    0.995532]  xhci_run from usb_add_hcd+0x444/0x6e0
[    1.000362]  usb_add_hcd from usb_hcd_pci_probe+0x30c/0x37c
[    1.005979]  usb_hcd_pci_probe from xhci_pci_probe+0x10/0xec
[    1.011689]  xhci_pci_probe from pci_device_probe+0x74/0xe8
[    1.017305]  pci_device_probe from really_probe+0x1c0/0x3f8
[    1.022921]  really_probe from driver_probe_device+0x30/0xb0
[    1.028623]  driver_probe_device from __driver_attach+0x11c/0x148
[    1.034762]  __driver_attach from bus_for_each_dev+0x54/0x78
[    1.040466]  bus_for_each_dev from bus_add_driver+0x170/0x1d8
[    1.046256]  bus_add_driver from driver_register+0xac/0xf0
[    1.051783]  driver_register from do_one_initcall+0x74/0x1b8
[    1.057495]  do_one_initcall from kernel_init_freeable+0x1a8/0x1ec
[    1.063723]  kernel_init_freeable from kernel_init+0x10/0x108
[    1.069514]  kernel_init from ret_from_fork+0x14/0x3c
[    1.074604] Exception stack(0xc1835fb0 to 0xc1835ff8)
[    1.079691] 5fa0:                                     00000000 00000000 00000000 00000000
[    1.087915] 5fc0: 00000000 00000000 00000000 00000000 00000000 00000000 00000000 00000000
[    1.096136] 5fe0: 00000000 00000000 00000000 00000000 00000013 00000000
[    1.102787] ---[ end trace 0000000000000000 ]---
[    1.107435] ------------[ cut here ]------------


I bisected it down to commit 077ee78e392869e46ae (PCI/MSI: Make
arch_.*_msi_irq[s] fallbacks selectable).

Re-enabling PCI/MSI arch fallbacks restores a clean bootlog.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Domenico Andreoli <domenico.andreoli@linux.com>

---
 arch/arm/mach-mvebu/Kconfig |    1 +
 1 file changed, 1 insertion(+)

Index: b/arch/arm/mach-mvebu/Kconfig
===================================================================

--- a/arch/arm/mach-mvebu/Kconfig
+++ b/arch/arm/mach-mvebu/Kconfig
@@ -123,6 +123,7 @@ config MACH_KIRKWOOD
 	select ORION_IRQCHIP
 	select ORION_TIMER
 	select FORCE_PCI
+	select PCI_MSI_ARCH_FALLBACKS if PCI_MSI
 	select PCI_QUIRKS
 	select PINCTRL_KIRKWOOD
 	help


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