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Date: Fri, 02 Nov 2012 21:25:42 +0100
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Bjorn Helgaas <bhelgaas@...gle.com>
Cc: Huang Ying <ying.huang@...el.com>, linux-kernel@...r.kernel.org,
linux-pci@...r.kernel.org, linux-pm@...r.kernel.org,
stable@...r.kernel.org
Subject: Re: [BUGFIX] PCI/PM: Fix proc config reg access for D3cold and bridge suspending
On Friday, November 02, 2012 10:38:43 AM Bjorn Helgaas wrote:
> On Wed, Oct 24, 2012 at 7:36 PM, Huang Ying <ying.huang@...el.com> wrote:
> > In
> >
> > https://bugzilla.kernel.org/show_bug.cgi?id=48981
> >
> > Peter reported that /proc/bus/pci/??/??.? does not works for 3.6.
> > This is This is because the device configuration space registers will
> > be not accessible if the corresponding parent bridge is suspended or
> > the device is put into D3cold state.
> >
> > This is the same as /sys/bus/pci/devices/0000:??:??.?/config access
> > issue. So the function used to solve sysfs issue is used to solve
> > this issue.
> >
> > Cc: stable@...r.kernel.org
> > Reported-by: Peter <lekensteyn@...il.com>
>
> Is this bug the same as the one originally reported by Forrest Loomis
> (original reporter of bug 48981)? And
> https://bugzilla.kernel.org/show_bug.cgi?id=49031, reported by Micael
> Dias (Rafael marked 49031 as a duplicate of 48981)?
>
> If so, I'll mention Forrest and Micael and bug 49031 here as well.
No, it's not. That one turned out to be a duplicate of bko#48981.
Thanks,
Rafael
> > Signed-off-by: Huang Ying <ying.huang@...el.com>
> > ---
> > drivers/pci/pci-sysfs.c | 34 ----------------------------------
> > drivers/pci/pci.c | 32 ++++++++++++++++++++++++++++++++
> > drivers/pci/pci.h | 2 ++
> > drivers/pci/proc.c | 8 ++++++++
> > 4 files changed, 42 insertions(+), 34 deletions(-)
> >
> > --- a/drivers/pci/pci-sysfs.c
> > +++ b/drivers/pci/pci-sysfs.c
> > @@ -458,40 +458,6 @@ boot_vga_show(struct device *dev, struct
> > }
> > struct device_attribute vga_attr = __ATTR_RO(boot_vga);
> >
> > -static void
> > -pci_config_pm_runtime_get(struct pci_dev *pdev)
> > -{
> > - struct device *dev = &pdev->dev;
> > - struct device *parent = dev->parent;
> > -
> > - if (parent)
> > - pm_runtime_get_sync(parent);
> > - pm_runtime_get_noresume(dev);
> > - /*
> > - * pdev->current_state is set to PCI_D3cold during suspending,
> > - * so wait until suspending completes
> > - */
> > - pm_runtime_barrier(dev);
> > - /*
> > - * Only need to resume devices in D3cold, because config
> > - * registers are still accessible for devices suspended but
> > - * not in D3cold.
> > - */
> > - if (pdev->current_state == PCI_D3cold)
> > - pm_runtime_resume(dev);
> > -}
> > -
> > -static void
> > -pci_config_pm_runtime_put(struct pci_dev *pdev)
> > -{
> > - struct device *dev = &pdev->dev;
> > - struct device *parent = dev->parent;
> > -
> > - pm_runtime_put(dev);
> > - if (parent)
> > - pm_runtime_put_sync(parent);
> > -}
> > -
> > static ssize_t
> > pci_read_config(struct file *filp, struct kobject *kobj,
> > struct bin_attribute *bin_attr,
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -1858,6 +1858,38 @@ bool pci_dev_run_wake(struct pci_dev *de
> > }
> > EXPORT_SYMBOL_GPL(pci_dev_run_wake);
> >
> > +void pci_config_pm_runtime_get(struct pci_dev *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct device *parent = dev->parent;
> > +
> > + if (parent)
> > + pm_runtime_get_sync(parent);
> > + pm_runtime_get_noresume(dev);
> > + /*
> > + * pdev->current_state is set to PCI_D3cold during suspending,
> > + * so wait until suspending completes
> > + */
> > + pm_runtime_barrier(dev);
> > + /*
> > + * Only need to resume devices in D3cold, because config
> > + * registers are still accessible for devices suspended but
> > + * not in D3cold.
> > + */
> > + if (pdev->current_state == PCI_D3cold)
> > + pm_runtime_resume(dev);
> > +}
> > +
> > +void pci_config_pm_runtime_put(struct pci_dev *pdev)
> > +{
> > + struct device *dev = &pdev->dev;
> > + struct device *parent = dev->parent;
> > +
> > + pm_runtime_put(dev);
> > + if (parent)
> > + pm_runtime_put_sync(parent);
> > +}
> > +
> > /**
> > * pci_pm_init - Initialize PM functions of given PCI device
> > * @dev: PCI device to handle.
> > --- a/drivers/pci/pci.h
> > +++ b/drivers/pci/pci.h
> > @@ -72,6 +72,8 @@ extern void pci_disable_enabled_device(s
> > extern int pci_finish_runtime_suspend(struct pci_dev *dev);
> > extern int __pci_pme_wakeup(struct pci_dev *dev, void *ign);
> > extern void pci_wakeup_bus(struct pci_bus *bus);
> > +extern void pci_config_pm_runtime_get(struct pci_dev *dev);
> > +extern void pci_config_pm_runtime_put(struct pci_dev *dev);
> > extern void pci_pm_init(struct pci_dev *dev);
> > extern void platform_pci_wakeup_init(struct pci_dev *dev);
> > extern void pci_allocate_cap_save_buffers(struct pci_dev *dev);
> > --- a/drivers/pci/proc.c
> > +++ b/drivers/pci/proc.c
> > @@ -76,6 +76,8 @@ proc_bus_pci_read(struct file *file, cha
> > if (!access_ok(VERIFY_WRITE, buf, cnt))
> > return -EINVAL;
> >
> > + pci_config_pm_runtime_get(dev);
> > +
> > if ((pos & 1) && cnt) {
> > unsigned char val;
> > pci_user_read_config_byte(dev, pos, &val);
> > @@ -121,6 +123,8 @@ proc_bus_pci_read(struct file *file, cha
> > cnt--;
> > }
> >
> > + pci_config_pm_runtime_put(dev);
> > +
> > *ppos = pos;
> > return nbytes;
> > }
> > @@ -146,6 +150,8 @@ proc_bus_pci_write(struct file *file, co
> > if (!access_ok(VERIFY_READ, buf, cnt))
> > return -EINVAL;
> >
> > + pci_config_pm_runtime_get(dev);
> > +
> > if ((pos & 1) && cnt) {
> > unsigned char val;
> > __get_user(val, buf);
> > @@ -191,6 +197,8 @@ proc_bus_pci_write(struct file *file, co
> > cnt--;
> > }
> >
> > + pci_config_pm_runtime_put(dev);
> > +
> > *ppos = pos;
> > i_size_write(ino, dp->size);
> > return nbytes;
> > --
> > To unsubscribe from this list: send the line "unsubscribe linux-pci" in
> > the body of a message to majordomo@...r.kernel.org
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>
--
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.
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