[PATCH v2 10/13] PCI/portdrv: Remove "pcie_hp=nomsi" kernel parameter

From: Bjorn Helgaas
Date: Fri Mar 09 2018 - 14:00:49 EST


From: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>

7570a333d8b0 ("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 fda78d7a0ead ("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 7570a333d8b0 to remove the "pcie_hp=nomsi" parameter.

Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Reviewed-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
CC: MUNEDA Takahiro <muneda.takahiro@xxxxxxxxxxxxxx>
CC: Kenji Kaneshige <kaneshige.kenji@xxxxxxxxxxxxxx>
CC: Prarit Bhargava <prarit@xxxxxxxxxx>
---
Documentation/admin-guide/kernel-parameters.txt | 4 ----
drivers/pci/pcie/portdrv.h | 12 ------------
drivers/pci/pcie/portdrv_core.c | 20 +++-----------------
3 files changed, 3 insertions(+), 33 deletions(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 1d1d53f85ddd..761749562165 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -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
diff --git a/drivers/pci/pcie/portdrv.h b/drivers/pci/pcie/portdrv.h
index ed84e767085f..86368f9341d7 100644
--- a/drivers/pci/pcie/portdrv.h
+++ b/drivers/pci/pcie/portdrv.h
@@ -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;

diff --git a/drivers/pci/pcie/portdrv_core.c b/drivers/pci/pcie/portdrv_core.c
index 589960fdd8a8..ed24a407518a 100644
--- a/drivers/pci/pcie/portdrv_core.c
+++ b/drivers/pci/pcie/portdrv_core.c
@@ -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;