2007/8/7, Rafael J. Wysocki <[email protected]>:
> On Monday, 6 August 2007 17:50, Joonwoo Park wrote:
> > 2007/8/6, Rafael J. Wysocki <[email protected]>:
> > > On Monday, 6 August 2007 15:42, Joonwoo Park wrote:
> > > > Hi.
> > > > I think that the pci_set_power_state() has bug.
> > > > The specification says that some delays is required.
> > >
> > > And they are in place, AFAICS (from drivers/pci/pci.c):
> > >
> > > /* Mandatory power management transition delays */
> > > /* see PCI PM 1.1 5.6.1 table 18 */
> > > if (state == PCI_D3hot || dev->current_state == PCI_D3hot)
> > > msleep(pci_pm_d3_delay);
> > > else if (state == PCI_D2 || dev->current_state == PCI_D2)
> > > udelay(200);
> > >
> >
> > The problem is occurred when state is 'PCI_D0', so those codes can't cover it.
> > But pci pm specification 5.4.1 says that when programmed to D0 the
> > equivalent of a warm reset, delay for the duration of the D3hot to D0
> > Uninitialized state
> > transition (10ms) to pci signal drivers remain disabled is required.
>
> Section 5.4.1 of PCI PM 1.1. spec is about D3_hot. Specifically, it says
> that if a device in D3_hot is programmed to D0, it performs the equivalent of
> a warm reset. IOW, this is supposed to happen if the current state is D3_hot
> and the targed state is D0, which is covered by the code snippet above.
IMHO, it is seems to the spec says just *programmed to D0* not
*programmed from D3hot to D0*.
Actually, I got current_state UNKNOWN and state PCI_D0 after kexec's
start new kernel with dual port 82546EB fiber ethernet card.
>
> Greetings,
> Rafael
>
>
> --
> "Premature optimization is the root of all evil." - Donald Knuth
>
Simon, this patch was checked with checkpatch.pl and fixed some fault.
Signed-off-by: Joonwoo Park <[email protected]>
---
drivers/pci/pci.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 37c00f6..0f086d9 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -467,7 +467,8 @@ pci_set_power_state(struct pci_dev *dev, pci_power_t state)
/* Mandatory power management transition delays */
/* see PCI PM 1.1 5.6.1 table 18 */
- if (state == PCI_D3hot || dev->current_state == PCI_D3hot)
+ if (state == PCI_D3hot || dev->current_state == PCI_D3hot ||
+ state == PCI_D0)
msleep(pci_pm_d3_delay);
else if (state == PCI_D2 || dev->current_state == PCI_D2)
udelay(200);
-
Best regards,
Joonwoo Park.
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
