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PCI/portdrv: Remove "pcie_hp=nomsi" kernel parameter 

7570a333d8 ("PCI: Add pcie_hp=nomsi to disable MSI/MSI-X for pciehp
driver") added the "pcie_hp=nomsi" kernel parameter to work around this
error on shutdown:

  irq 16: nobody cared (try booting with the "irqpoll" option)
  Pid: 1081, comm: reboot Not tainted 3.2.0 #1
  ...
  Disabling IRQ #16

This happened on an unspecified system (possibly involving the Integrated
Device Technology, Inc. Device 807f bridge) where "an un-wanted interrupt
is generated when PCI driver switches from MSI/MSI-X to INTx while shutting
down the device."

The implication was that the device was buggy, but it is normal for a
device to use INTx after MSI/MSI-X have been disabled.  The only problem
was that the driver was still attached and it wasn't prepared for INTx
interrupts.  Prarit Bhargava fixed this issue with fda78d7a0e ("PCI/MSI:
Stop disabling MSI/MSI-X in pci_device_shutdown()").

There is no automated way to set this parameter, so it's not very useful
for distributions or end users.  It's really only useful for debugging, and
we have "pci=nomsi" for that purpose.

Revert 7570a333d8 to remove the "pcie_hp=nomsi" parameter.

Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
CC: MUNEDA Takahiro <muneda.takahiro@jp.fujitsu.com>
CC: Kenji Kaneshige <kaneshige.kenji@jp.fujitsu.com>
CC: Prarit Bhargava <prarit@redhat.com>
This commit is contained in:
Bjorn Helgaas 2018-03-09 11:21:27 -06:00 committed by Bjorn Helgaas
parent 1b64cb87cf
commit 1e447c57ae
3 changed files with 3 additions and 33 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
Documentation/admin-guide/kernel-parameters.txt
View File

@ -3130,10 +3130,6 @@
force Enable ASPM even on devices that claim not to support it.
WARNING: Forcing ASPM on may cause system lockups.
pcie_hp= [PCIE] PCI Express Hotplug driver options:
nomsi Do not use MSI for PCI Express Native Hotplug (this
makes all PCIe ports use INTx for hotplug services).
pcie_ports= [PCIE] PCIe ports handling:
auto Ask the BIOS whether or not to use native PCIe services
associated with PCIe ports (PME, hot-plug, AER). Use

12
drivers/pci/pcie/portdrv.h
View File

@ -91,18 +91,6 @@ void pcie_port_bus_unregister(void);
struct pci_dev;
#ifdef CONFIG_HOTPLUG_PCI_PCIE
extern bool pciehp_msi_disabled;
static inline bool pciehp_no_msi(void)
{
return pciehp_msi_disabled;
}
#else /* !CONFIG_HOTPLUG_PCI_PCIE */
static inline bool pciehp_no_msi(void) { return false; }
#endif /* !CONFIG_HOTPLUG_PCI_PCIE */
#ifdef CONFIG_PCIE_PME
extern bool pcie_pme_msi_disabled;

20
drivers/pci/pcie/portdrv_core.c
View File

@ -20,17 +20,6 @@
#include "../pci.h"
#include "portdrv.h"
bool pciehp_msi_disabled;
static int __init pciehp_setup(char *str)
{
if (!strncmp(str, "nomsi", 5))
pciehp_msi_disabled = true;
return 1;
}
__setup("pcie_hp=", pciehp_setup);
/**
* release_pcie_device - free PCI Express port service device structure
* @dev: Port service device to release
@ -168,16 +157,13 @@ static int pcie_init_service_irqs(struct pci_dev *dev, int *irqs, int mask)
irqs[i] = -1;
/*
* If we support PME or hotplug, but we can't use MSI/MSI-X for
* them, we have to fall back to INTx or other interrupts, e.g., a
* system shared interrupt.
* If we support PME but can't use MSI/MSI-X for it, we have to
* fall back to INTx or other interrupts, e.g., a system shared
* interrupt.
*/
if ((mask & PCIE_PORT_SERVICE_PME) && pcie_pme_no_msi())
goto legacy_irq;
if ((mask & PCIE_PORT_SERVICE_HP) && pciehp_no_msi())
goto legacy_irq;
/* Try to use MSI-X or MSI if supported */
if (pcie_port_enable_irq_vec(dev, irqs, mask) == 0)
return 0;