[PATCH] usb: musb: PM: fix context save/restore in suspend/resume path

[PATCH] usb: musb: PM: fix context save/restore in suspend/resume path

[Kevin Hilman]

Currently the driver tries to save context in the suspend path, but
will cause an abort if the device is already runtime suspended.  This
happens, for example, if MUSB loaded/compiled-in, in host mode, but no
USB devices are attached.  MUSB will be runtime suspended, but then
attempting a system suspend will crash due to the context save
being attempted while the device is disabled.

On OMAP, as of v3.1, the driver's ->runtime_suspend() callback will be
called late in the suspend path (by the PM domain layer) if the driver
is not already runtime suspended, ensuring a full shutdown.

Therefore, the context save is not needed in the ->suspend() method
since it will be called in the ->runtime_suspend() method anyways
(similarily for resume.)

NOTE: this leaves the suspend/resume methods basically empty (with
      some FIXMEs and comments, but I'll leave it to the maintainers
      to decide whether to remove them.

Signed-off-by: Kevin Hilman <khilman@ti.com>
---
 drivers/usb/musb/musb_core.c |    6 ------
 1 files changed, 0 insertions(+), 6 deletions(-)

diff --git a/drivers/usb/musb/musb_core.c b/drivers/usb/musb/musb_core.c
index 20a2873..a057a5a 100644
--- a/drivers/usb/musb/musb_core.c
+++ b/drivers/usb/musb/musb_core.c
@@ -2302,18 +2302,12 @@ static int musb_suspend(struct device *dev)
 		 */
 	}
 
-	musb_save_context(musb);
-
 	spin_unlock_irqrestore(&musb->lock, flags);
 	return 0;
 }
 
 static int musb_resume_noirq(struct device *dev)
 {
-	struct musb	*musb = dev_to_musb(dev);
-
-	musb_restore_context(musb);
-
 	/* for static cmos like DaVinci, register values were preserved
 	 * unless for some reason the whole soc powered down or the USB
 	 * module got reset through the PSC (vs just being disabled).
-- 
1.7.6

Re: [PATCH] usb: musb: PM: fix context save/restore in suspend/resume path

[Felipe Balbi]

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Hi,

On Tue, Nov 22, 2011 at 05:18:24PM -0800, Kevin Hilman wrote:
> Currently the driver tries to save context in the suspend path, but
> will cause an abort if the device is already runtime suspended.  This
> happens, for example, if MUSB loaded/compiled-in, in host mode, but no
> USB devices are attached.  MUSB will be runtime suspended, but then
> attempting a system suspend will crash due to the context save
> being attempted while the device is disabled.
> 
> On OMAP, as of v3.1, the driver's ->runtime_suspend() callback will be
> called late in the suspend path (by the PM domain layer) if the driver
> is not already runtime suspended, ensuring a full shutdown.
> 
> Therefore, the context save is not needed in the ->suspend() method
> since it will be called in the ->runtime_suspend() method anyways
> (similarily for resume.)
> 
> NOTE: this leaves the suspend/resume methods basically empty (with
>       some FIXMEs and comments, but I'll leave it to the maintainers
>       to decide whether to remove them.
> 
> Signed-off-by: Kevin Hilman <khilman@ti.com>

3.1 ? so this should go to stable too, right ?

-- 
balbi

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Re: [PATCH] usb: musb: PM: fix context save/restore in suspend/resume path

[Felipe Balbi]

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Hi,

On Tue, Nov 22, 2011 at 05:18:24PM -0800, Kevin Hilman wrote:
> Currently the driver tries to save context in the suspend path, but
> will cause an abort if the device is already runtime suspended.  This
> happens, for example, if MUSB loaded/compiled-in, in host mode, but no
> USB devices are attached.  MUSB will be runtime suspended, but then
> attempting a system suspend will crash due to the context save
> being attempted while the device is disabled.
> 
> On OMAP, as of v3.1, the driver's ->runtime_suspend() callback will be
> called late in the suspend path (by the PM domain layer) if the driver
> is not already runtime suspended, ensuring a full shutdown.
> 
> Therefore, the context save is not needed in the ->suspend() method
> since it will be called in the ->runtime_suspend() method anyways
> (similarily for resume.)
> 
> NOTE: this leaves the suspend/resume methods basically empty (with
>       some FIXMEs and comments, but I'll leave it to the maintainers
>       to decide whether to remove them.
> 
> Signed-off-by: Kevin Hilman <khilman@ti.com>

applied, thanks.

I've added Cc: stable@vger.kernel.org so that this goes to v3.1 too.

-- 
balbi

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