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[4/4] pci pm: follow PCI_PM_CTRL_NO_SOFT_RESET during transitions from D3

Message ID 200906101956.n5AJuXtJ009522@imap1.linux-foundation.org (mailing list archive)
State Accepted, archived
Headers show

Commit Message

Andrew Morton June 10, 2009, 7:56 p.m. UTC 
From: Rafael J. Wysocki <rjw@sisk.pl>

According to the PCI PM specification (PCI Bus Power Management Interface
Specification, Rev.  1.2, Section 5.4.1) we are supposed to reinitialize
devices that have PCI_PM_CTRL_NO_SOFT_RESET clear during all transitions
from PCI_D3hot to PCI_D0, but we only do it if the device's current_state
field is equal to PCI_UNKNOWN.

This may lead to problems if a device with PCI_PM_CTRL_NO_SOFT_RESET unset
is put into PCI_D3hot at run time by its driver and pci_set_power_state()
is used to put it back into PCI_D0, because in that case the device will
remain uninitialized after pci_set_power_state() has returned.  Prevent
that from happening by modifying pci_raw_set_power_state() to reinitialize
devices with PCI_PM_CTRL_NO_SOFT_RESET unset during all transitions from
D3 to D0.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/pci/pci.c |    2 ++
 1 file changed, 2 insertions(+)
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Patch

diff -puN drivers/pci/pci.c~pci-pm-follow-pci_pm_ctrl_no_soft_reset-during-transitions-from-d3 drivers/pci/pci.c
--- a/drivers/pci/pci.c~pci-pm-follow-pci_pm_ctrl_no_soft_reset-during-transitions-from-d3
+++ a/drivers/pci/pci.c
@@ -485,6 +485,8 @@  static int pci_raw_set_power_state(struc
 		pmcsr &= ~PCI_PM_CTRL_STATE_MASK;
 		pmcsr |= state;
 		break;
+	case PCI_D3hot:
+	case PCI_D3cold:
 	case PCI_UNKNOWN: /* Boot-up */
 		if ((pmcsr & PCI_PM_CTRL_STATE_MASK) == PCI_D3hot
 		 && !(pmcsr & PCI_PM_CTRL_NO_SOFT_RESET))