Re: [RFC][PATCH -mm] PM: Do not use saved_state from struct dev_pm_info on ARM (was: Re: patch pm-remove-saved_state-from-struct-dev_pm_info.patch added to gregkh-2.6 tree)

From: Rafael J. Wysocki
Date: Thu Jun 28 2007 - 11:41:53 EST


On Wednesday, 27 June 2007 23:11, Rafael J. Wysocki wrote:
> On Tuesday, 26 June 2007 23:03, Greg KH wrote:
> > On Tue, Jun 26, 2007 at 11:00:06PM +0200, Rafael J. Wysocki wrote:
> > > On Friday, 15 June 2007 00:57, gregkh@xxxxxxx wrote:
> > > >
> > > > This is a note to let you know that I've just added the patch titled
> > > >
> > > > Subject: PM: Remove saved_state from struct dev_pm_info
> > > >
> > > > to my gregkh-2.6 tree. Its filename is
> > > >
> > > > pm-remove-saved_state-from-struct-dev_pm_info.patch
> > > >
> > > > This tree can be found at
> > > > http://www.kernel.org/pub/linux/kernel/people/gregkh/gregkh-2.6/patches/
> > > >
> > > >
> > > > From rjw@xxxxxxx Thu Jun 14 15:47:15 2007
> > > > From: "Rafael J. Wysocki" <rjw@xxxxxxx>
> > > > To: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
> > > > Subject: PM: Remove saved_state from struct dev_pm_info
> > > > Date: Wed, 13 Jun 2007 15:55:34 +0200
> > > > Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>, David Brownell <david-b@xxxxxxxxxxx>, Greg KH <greg@xxxxxxxxx>, Pavel Machek <pavel@xxxxxx>
> > > > Content-Disposition: inline
> > > > Message-Id: <200706131555.37277.rjw@xxxxxxx>
> > > >
> > > > From: Rafael J. Wysocki <rjw@xxxxxxx>
> > > >
> > > > The saved_state member of struct dev_pm_info, defined in include/linux/pm.h, is
> > > > not used anywhere, so it can be removed.
> > >
> > > Unfortunately this is wrong, as I've just found three drivers in the ARM tree
> > > that use it. I don't know why I didn't see them when I was creating the patch,
> > > though. :-(
> >
> > Why not just fix up the ARM drivers instead?
>
> OK, let's try. :-)
>
> The following patch has only been compilation tested.
>
> ---
> From: Rafael J. Wysocki <rjw@xxxxxxx>
>
> The saved_state member of 'struct dev_pm_info' that's going to be removed is
> used in arch/arm/common/locomo.c, arch/arm/common/sa1111.c and
> arch/arm/mach-sa1100/neponset.c. Change the code in there to use local
> variables for saving the state of devices during suspend.
>
> Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>

Russell says that the affected drivers were coded to support multiple instances
of the same device which the $subject patch doesn't take into account (still,
as far as the neponset is concerned, I think that there can be only one
instance of NCR_0 in the system).

Updated (compilation tested) patch follows.

Greetings,
Rafael


---
From: Rafael J. Wysocki <rjw@xxxxxxx>

The saved_state member of 'struct dev_pm_info' that's going to be removed is
used in arch/arm/common/locomo.c, arch/arm/common/sa1111.c and
arch/arm/mach-sa1100/neponset.c. Change the code in there to use the drivers'
own per-device data structures or static variables for saving the state of
devices during suspend.

Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx>
---
arch/arm/common/locomo.c | 9 +++++++--
arch/arm/common/sa1111.c | 13 ++++++++-----
arch/arm/mach-sa1100/neponset.c | 15 ++++-----------
3 files changed, 19 insertions(+), 18 deletions(-)

Index: linux-2.6.22-rc6/arch/arm/common/locomo.c
===================================================================
--- linux-2.6.22-rc6.orig/arch/arm/common/locomo.c
+++ linux-2.6.22-rc6/arch/arm/common/locomo.c
@@ -60,6 +60,9 @@ struct locomo {
unsigned int irq;
spinlock_t lock;
void __iomem *base;
+#ifdef CONFIG_PM
+ void *saved_state;
+#endif
};

struct locomo_dev_info {
@@ -565,7 +568,7 @@ static int locomo_suspend(struct platfor
if (!save)
return -ENOMEM;

- dev->dev.power.saved_state = (void *) save;
+ lchip->saved_state = save;

spin_lock_irqsave(&lchip->lock, flags);

@@ -606,7 +609,7 @@ static int locomo_resume(struct platform
unsigned long r;
unsigned long flags;

- save = (struct locomo_save_data *) dev->dev.power.saved_state;
+ save = lchip->saved_state;
if (!save)
return 0;

@@ -628,6 +631,8 @@ static int locomo_resume(struct platform
locomo_writel(0x1, lchip->base + LOCOMO_KEYBOARD + LOCOMO_KCMD);

spin_unlock_irqrestore(&lchip->lock, flags);
+
+ lchip->saved_state = NULL;
kfree(save);

return 0;
Index: linux-2.6.22-rc6/arch/arm/common/sa1111.c
===================================================================
--- linux-2.6.22-rc6.orig/arch/arm/common/sa1111.c
+++ linux-2.6.22-rc6/arch/arm/common/sa1111.c
@@ -51,6 +51,9 @@ struct sa1111 {
int irq;
spinlock_t lock;
void __iomem *base;
+#ifdef CONFIG_PM
+ void *saved_state;
+#endif
};

/*
@@ -822,7 +825,7 @@ static int sa1111_suspend(struct platfor
save = kmalloc(sizeof(struct sa1111_save_data), GFP_KERNEL);
if (!save)
return -ENOMEM;
- dev->dev.power.saved_state = save;
+ sachip->saved_state = save;

spin_lock_irqsave(&sachip->lock, flags);

@@ -878,7 +881,7 @@ static int sa1111_resume(struct platform
unsigned long flags, id;
void __iomem *base;

- save = (struct sa1111_save_data *)dev->dev.power.saved_state;
+ save = sachip->saved_state;
if (!save)
return 0;

@@ -923,7 +926,7 @@ static int sa1111_resume(struct platform

spin_unlock_irqrestore(&sachip->lock, flags);

- dev->dev.power.saved_state = NULL;
+ sachip->saved_state = NULL;
kfree(save);

return 0;
@@ -958,8 +961,8 @@ static int sa1111_remove(struct platform
platform_set_drvdata(pdev, NULL);

#ifdef CONFIG_PM
- kfree(pdev->dev.power.saved_state);
- pdev->dev.power.saved_state = NULL;
+ kfree(sachip->saved_state);
+ sachip->saved_state = NULL;
#endif
}

Index: linux-2.6.22-rc6/arch/arm/mach-sa1100/neponset.c
===================================================================
--- linux-2.6.22-rc6.orig/arch/arm/mach-sa1100/neponset.c
+++ linux-2.6.22-rc6/arch/arm/mach-sa1100/neponset.c
@@ -185,28 +185,21 @@ static int __devinit neponset_probe(stru
/*
* LDM power management.
*/
+static unsigned int neponset_saved_state;
+
static int neponset_suspend(struct platform_device *dev, pm_message_t state)
{
/*
* Save state.
*/
- if (!dev->dev.power.saved_state)
- dev->dev.power.saved_state = kmalloc(sizeof(unsigned int), GFP_KERNEL);
- if (!dev->dev.power.saved_state)
- return -ENOMEM;
-
- *(unsigned int *)dev->dev.power.saved_state = NCR_0;
+ neponset_saved_state = NCR_0;

return 0;
}

static int neponset_resume(struct platform_device *dev)
{
- if (dev->dev.power.saved_state) {
- NCR_0 = *(unsigned int *)dev->dev.power.saved_state;
- kfree(dev->dev.power.saved_state);
- dev->dev.power.saved_state = NULL;
- }
+ NCR_0 = neponset_saved_state;

return 0;
}
-
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