Re: [PATCH] PCI: Document connection between pci_power_t and hardware PM capability

[Bjorn Helgaas <helgaas@kernel.org>]

On Sun, Jun 19, 2016 at 02:49:46PM +0300, Andy Shevchenko wrote:
> On Sat, 2016-06-18 at 13:00 -0500, Bjorn Helgaas wrote:
> > The dev.pme_support field, pci_pm_init(), and pci_pme_capable() depend
> > on
> > the fact that the pci_power_t values (PCI_D0, PCI_D1, etc.) match the
> > definition of the PME_Support field of the Power Management
> > Capabilities
> > register in the Power Management capability (see PCI Bus Power
> > Management
> > spec r1.2, sec 3.2.3).
> 
> Nice to know! Thanks.
> 
> If it matters:
> Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

Definitely!  I updated based on Lukas' comment and added your and Mika's
Reviewed-by:

commit 224abb67e6eb5ac062de9239163136d5ec3155c8
Author: Bjorn Helgaas <bhelgaas@google.com>
Date:   Fri Jun 17 15:23:52 2016 -0500

    PCI: Document connection between pci_power_t and hardware PM capability
    
    The dev.pme_support field, pci_pm_init(), pci_pme_capable(), and
    pci_raw_set_power_state() depend on the fact that the pci_power_t values
    (PCI_D0, PCI_D1, etc.) match the definition of the Capabilities PME_Support
    and the Control/Status PowerState fields in the Power Management capability
    (see PCI Bus Power Management spec r1.2, sec 3.2.3).
    
    Add a note to this effect at the pci_power_t typedef.
    
    Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
    Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
    Reviewed-by: Mika Westerberg <mika.westerberg@linux.intel.com>

diff --git a/include/linux/pci.h b/include/linux/pci.h
index 8597b42..0a1a9e3 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -101,6 +101,10 @@ enum {
 	DEVICE_COUNT_RESOURCE = PCI_NUM_RESOURCES,
 };
 
+/*
+ * pci_power_t values must match the bits in the Capabilities PME_Support
+ * and Control/Status PowerState fields in the Power Management capability.
+ */
 typedef int __bitwise pci_power_t;
 
 #define PCI_D0		((pci_power_t __force) 0)