We used to assign IRQs for all devices at boot-time, before any drivers
claimed devices.  The following commits:

  30fdfb92 ("PCI: Add a call to pci_assign_irq() in pci_device_probe()")
  0e4c2eeb ("alpha/PCI: Replace pci_fixup_irqs() call with host bridge IRQ mapping hooks")

changed this so we now call pci_assign_irq() from pci_device_probe() when
we call a driver's probe method.

The ide_scan_pcibus() path (enabled by CONFIG_IDEPCI_PCIBUS_ORDER) bypasses
pci_device_probe() so it can guarantee devices are claimed in order of PCI
bus address.  It calls the driver's probe method directly, so it misses the
pci_assign_irq() call (and other PCI initialization functions), which
causes failures like this:

  ide0: disabled, no IRQ
  ide0: failed to initialize IDE interface
  ide0: disabling port
  cmd64x 0000:00:02.0: IDE controller (0x1095:0x0646 rev 0x07)
  CMD64x_IDE 0000:00:02.0: BAR 0: can't reserve [io  0x8050-0x8057]
  cmd64x 0000:00:02.0: can't reserve resources
  CMD64x_IDE: probe of 0000:00:02.0 failed with error -16
  ide_generic: please use "probe_mask=0x3f" module parameter for probing
  all legacy ISA IDE ports
  ------------[ cut here ]------------
  WARNING: CPU: 0 PID: 1 at fs/sysfs/dir.c:31 sysfs_warn_dup+0x94/0xd0
  sysfs: cannot create duplicate filename '/class/ide_port/ide0'
  ...

  Trace:
  [<fffffc000048c9f4>] sysfs_warn_dup+0x94/0xd0
  [<fffffc0000330928>] warn_slowpath_fmt+0x58/0x70
  [<fffffc000048c9f4>] sysfs_warn_dup+0x94/0xd0
  [<fffffc0000486d40>] kernfs_path_from_node+0x30/0x60
  [<fffffc00004874ac>] kernfs_put+0x16c/0x2c0
  [<fffffc00004874ac>] kernfs_put+0x16c/0x2c0
  [<fffffc000048d010>] sysfs_do_create_link_sd.isra.2+0x100/0x120
  [<fffffc00005b9d64>] device_add+0x2a4/0x7c0
  [<fffffc00005ba5cc>] device_create_groups_vargs+0x14c/0x170
  [<fffffc00005ba518>] device_create_groups_vargs+0x98/0x170
  [<fffffc00005ba690>] device_create+0x50/0x70
  [<fffffc00005df36c>] ide_host_register+0x48c/0xa00
  [<fffffc00005df330>] ide_host_register+0x450/0xa00
  [<fffffc00005ba2a0>] device_register+0x20/0x50
  [<fffffc00005df330>] ide_host_register+0x450/0xa00
  [<fffffc00005df944>] ide_host_add+0x64/0xe0
  [<fffffc000079b41c>] kobject_uevent_env+0x16c/0x710
  [<fffffc0000310288>] do_one_initcall+0x68/0x260
  [<fffffc00007b13bc>] kernel_init+0x1c/0x1a0
  ...
  ---[ end trace 24a70433c3e4d374 ]---
  ide0: disabling port

Fix the IRQ allocation issue by calling pci_assign_irq() from
ide_scan_pcidev() before probing the IDE PCI drivers, so that IRQs for a
given PCI device are allocated for the IDE PCI drivers to use them for
device configuration.

Fixes: 30fdfb92 ("PCI: Add a call to pci_assign_irq() in pci_device_probe()")
Fixes: 0e4c2eeb ("alpha/PCI: Replace pci_fixup_irqs() call with host bridge IRQ mapping hooks")
Link: http://lkml.kernel.org/r/32ec730f-c1b0-5584-cd35-f8a809122b96@roeck-us.netReported-by: Guenter Roeck <linux@roeck-us.net>
Tested-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
[bhelgaas: changelog]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Acked-by: David S. Miller <davem@davemloft.net>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>