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Date: Sat, 6 Dec 2008 02:18:12 +0100
From: "Rafael J. Wysocki" <rjw@...k.pl>
To: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Frans Pop <elendil@...net.nl>, Greg KH <greg@...ah.com>,
Ingo Molnar <mingo@...e.hu>, jbarnes@...tuousgeek.org,
lenb@...nel.org,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
tiwai@...e.de, Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: Regression from 2.6.26: Hibernation (possibly suspend) broken on Toshiba R500 (bisected)
On Saturday, 6 of December 2008, Linus Torvalds wrote:
>
> On Sat, 6 Dec 2008, Rafael J. Wysocki wrote:
> >
> > I tested the appended patch with suspend-to-RAM and it just hangs during
> > resume.
>
> That patch looks bogus. It only changes the "legacy" cases as far as I can
> tell, so anybogy who has drv->pm set will now not do any state save at
> all.
>
> Or am I misreading it?
It only affects the legacy handling, but the non-legacy handling was left
untouched. IOW, the old "default" functions are still there and are being
called by the "non-legacy" code (it's only used by USB at the moment, AFAICS).
Anyway, I did the test doing it only to the devices which don't have any
non-default suspend-resume handling at all and _that_ apparently fixed the
problem on my box. :-)
Appended is a very crude version of the patch (it duplicates some code),
tomorrow I'll post a cleaned-up version.
I'm still thinkig it will be reasonable to save standard config registers for
all devices with interrupts disabled, but that appears to be more complicated
that I thought it would be.
Thanks,
Rafael
---
drivers/pci/pci-driver.c | 66 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 66 insertions(+)
Index: linux-2.6/drivers/pci/pci-driver.c
===================================================================
--- linux-2.6.orig/drivers/pci/pci-driver.c
+++ linux-2.6/drivers/pci/pci-driver.c
@@ -300,6 +300,54 @@ static void pci_device_shutdown(struct d
#ifdef CONFIG_PM_SLEEP
+static void pci_default_suspend_noirq(struct pci_dev *pci_dev)
+{
+ dev_info(&pci_dev->dev, "saving standard PCI config registers\n");
+
+ /* save the PCI config space */
+ pci_save_state(pci_dev);
+ /*
+ * mark its power state as "unknown", since we don't know if
+ * e.g. the BIOS will change its device state when we suspend.
+ */
+ if (pci_dev->current_state == PCI_D0)
+ pci_dev->current_state = PCI_UNKNOWN;
+}
+
+static void pci_default_resume_noirq(struct pci_dev *pci_dev)
+{
+ dev_info(&pci_dev->dev, "restoring standard PCI config registers\n");
+
+ /* restore the PCI config space */
+ pci_restore_state(pci_dev);
+}
+
+static int pci_default_resume(struct pci_dev *pci_dev)
+{
+ int retval = 0;
+
+ dev_info(&pci_dev->dev, "trying to reenable device\n");
+
+ /* if the device was enabled before suspend, reenable */
+ retval = pci_reenable_device(pci_dev);
+ /*
+ * if the device was busmaster before the suspend, make it busmaster
+ * again
+ */
+ if (pci_dev->is_busmaster)
+ pci_set_master(pci_dev);
+
+ return retval;
+}
+
+static bool pci_has_legacy_pm_handling(struct pci_dev *pci_dev)
+{
+ struct pci_driver *drv = pci_dev->driver;
+
+ return drv && (drv->suspend || drv->suspend_late || drv->resume
+ || drv->resume_early);
+}
+
/*
* Default "suspend" method for devices that have no driver provided suspend,
* or not even a driver at all.
@@ -343,6 +391,9 @@ static int pci_legacy_suspend(struct dev
struct pci_driver * drv = pci_dev->driver;
int i = 0;
+ if (!pci_has_legacy_pm_handling(pci_dev))
+ return 0;
+
if (drv && drv->suspend) {
i = drv->suspend(pci_dev, state);
suspend_report_result(drv->suspend, i);
@@ -358,10 +409,16 @@ static int pci_legacy_suspend_late(struc
struct pci_driver * drv = pci_dev->driver;
int i = 0;
+ if (!pci_has_legacy_pm_handling(pci_dev)) {
+ pci_default_suspend_noirq(pci_dev);
+ return 0;
+ }
+
if (drv && drv->suspend_late) {
i = drv->suspend_late(pci_dev, state);
suspend_report_result(drv->suspend_late, i);
}
+
return i;
}
@@ -371,6 +428,9 @@ static int pci_legacy_resume(struct devi
struct pci_dev * pci_dev = to_pci_dev(dev);
struct pci_driver * drv = pci_dev->driver;
+ if (!pci_has_legacy_pm_handling(pci_dev))
+ return pci_default_resume(pci_dev);
+
if (drv && drv->resume)
error = drv->resume(pci_dev);
else
@@ -384,8 +444,14 @@ static int pci_legacy_resume_early(struc
struct pci_dev * pci_dev = to_pci_dev(dev);
struct pci_driver * drv = pci_dev->driver;
+ if (!pci_has_legacy_pm_handling(pci_dev)) {
+ pci_default_resume_noirq(pci_dev);
+ return 0;
+ }
+
if (drv && drv->resume_early)
error = drv->resume_early(pci_dev);
+
return error;
}
--
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