Re: [PATCH V2] USB: Increment wakeup count on remote wakeup.

[Ravi Chandra Sadineni]

On Fri, Apr 20, 2018 at 7:12 AM, Alan Stern  wrote:
> On Thu, 19 Apr 2018, Ravi Chandra Sadineni wrote:
>
>> On chromebooks we depend on wakeup count to identify the wakeup source.
>> But currently USB devices do not increment the wakeup count when they
>> trigger the remote wake. This patch addresses the same.
>>
>> Resume condition is reported differently on USB 2.0 and USB 3.0 devices.
>>
>> On USB 2.0 devices, a wake capable device, if wake enabled, drives
>> resume signal to indicate a remote wake (USB 2.0 spec section 7.1.7.7).
>> The upstream facing port then sets C_PORT_SUSPEND bit and reports a
>> port change event (USB 2.0 spec section 11.24.2.7.2.3). Thus if a port
>> has resumed before driving the resume signal from the host and
>> C_PORT_SUSPEND is set, then the device attached to the given port might
>> be the reason for the last system wakeup. Increment the wakeup count for
>> the same.
>>
>> On USB 3.0 devices, a function may signal that it wants to exit from device
>> suspend by sending a Function Wake Device Notification to the host (USB3.0
>> spec section 8.5.6.4) Thus on receiving the Function Wake, increment the
>> wakeup count.
>>
>> Signed-off-by: Ravi Chandra Sadineni 
>> ---
>>  drivers/usb/core/hcd.c |  2 ++
>>  drivers/usb/core/hub.c | 10 +-
>>  2 files changed, 11 insertions(+), 1 deletion(-)
>>
>> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
>> index 777036ae63674..ee0f3ec57ce49 100644
>> --- a/drivers/usb/core/hcd.c
>> +++ b/drivers/usb/core/hcd.c
>> @@ -2374,7 +2374,9 @@ static void hcd_resume_work(struct work_struct *work)
>>  void usb_hcd_resume_root_hub (struct usb_hcd *hcd)
>>  {
>>   unsigned long flags;
>> + struct device *dev = >self.root_hub->dev;
>>
>> + pm_wakeup_event(dev, 0);
>>   spin_lock_irqsave (_root_hub_lock, flags);
>>   if (hcd->rh_registered) {
>>   set_bit(HCD_FLAG_WAKEUP_PENDING, >flags);
>
> In general, hcd->self.root_hub is guaranteed to be non-NULL only when
> hcd->rh_registered is set.  Therefore the assignment to dev and the
> call to pm_wakeup_event() should be moved within this "if" statement.
>
> The rest of the patch looks okay.

Added the check in V3.  Thanks.
>
> Alan Stern
>
>> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
>> index f6ea16e9f6bb9..aa9968d90a48c 100644
>> --- a/drivers/usb/core/hub.c
>> +++ b/drivers/usb/core/hub.c
>> @@ -653,12 +653,17 @@ void usb_wakeup_notification(struct usb_device *hdev,
>>   unsigned int portnum)
>>  {
>>   struct usb_hub *hub;
>> + struct usb_port *port_dev;
>>
>>   if (!hdev)
>>   return;
>>
>>   hub = usb_hub_to_struct_hub(hdev);
>>   if (hub) {
>> + port_dev = hub->ports[portnum - 1];
>> + if (port_dev && port_dev->child)
>> + pm_wakeup_event(_dev->child->dev, 0);
>> +
>>   set_bit(portnum, hub->wakeup_bits);
>>   kick_hub_wq(hub);
>>   }
>> @@ -3434,8 +3439,11 @@ int usb_port_resume(struct usb_device *udev, 
>> pm_message_t msg)
>>
>>   /* Skip the initial Clear-Suspend step for a remote wakeup */
>>   status = hub_port_status(hub, port1, , );
>> - if (status == 0 && !port_is_suspended(hub, portstatus))
>> + if (status == 0 && !port_is_suspended(hub, portstatus)) {
>> + if (portchange & USB_PORT_STAT_C_SUSPEND)
>> + pm_wakeup_event(>dev, 0);
>>   goto SuspendCleared;
>> + }
>>
>>   /* see 7.1.7.7; affects power usage, but not budgeting */
>>   if (hub_is_superspeed(hub->hdev))
>>
>

Thanks,
Ravi
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Re: [PATCH V2] USB: Increment wakeup count on remote wakeup.

[Alan Stern]

On Thu, 19 Apr 2018, Ravi Chandra Sadineni wrote:

> On chromebooks we depend on wakeup count to identify the wakeup source.
> But currently USB devices do not increment the wakeup count when they
> trigger the remote wake. This patch addresses the same.
> 
> Resume condition is reported differently on USB 2.0 and USB 3.0 devices.
> 
> On USB 2.0 devices, a wake capable device, if wake enabled, drives
> resume signal to indicate a remote wake (USB 2.0 spec section 7.1.7.7).
> The upstream facing port then sets C_PORT_SUSPEND bit and reports a
> port change event (USB 2.0 spec section 11.24.2.7.2.3). Thus if a port
> has resumed before driving the resume signal from the host and
> C_PORT_SUSPEND is set, then the device attached to the given port might
> be the reason for the last system wakeup. Increment the wakeup count for
> the same.
> 
> On USB 3.0 devices, a function may signal that it wants to exit from device
> suspend by sending a Function Wake Device Notification to the host (USB3.0
> spec section 8.5.6.4) Thus on receiving the Function Wake, increment the
> wakeup count.
> 
> Signed-off-by: Ravi Chandra Sadineni 
> ---
>  drivers/usb/core/hcd.c |  2 ++
>  drivers/usb/core/hub.c | 10 +-
>  2 files changed, 11 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
> index 777036ae63674..ee0f3ec57ce49 100644
> --- a/drivers/usb/core/hcd.c
> +++ b/drivers/usb/core/hcd.c
> @@ -2374,7 +2374,9 @@ static void hcd_resume_work(struct work_struct *work)
>  void usb_hcd_resume_root_hub (struct usb_hcd *hcd)
>  {
>   unsigned long flags;
> + struct device *dev = >self.root_hub->dev;
>  
> + pm_wakeup_event(dev, 0);
>   spin_lock_irqsave (_root_hub_lock, flags);
>   if (hcd->rh_registered) {
>   set_bit(HCD_FLAG_WAKEUP_PENDING, >flags);

In general, hcd->self.root_hub is guaranteed to be non-NULL only when 
hcd->rh_registered is set.  Therefore the assignment to dev and the 
call to pm_wakeup_event() should be moved within this "if" statement.

The rest of the patch looks okay.

Alan Stern

> diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
> index f6ea16e9f6bb9..aa9968d90a48c 100644
> --- a/drivers/usb/core/hub.c
> +++ b/drivers/usb/core/hub.c
> @@ -653,12 +653,17 @@ void usb_wakeup_notification(struct usb_device *hdev,
>   unsigned int portnum)
>  {
>   struct usb_hub *hub;
> + struct usb_port *port_dev;
>  
>   if (!hdev)
>   return;
>  
>   hub = usb_hub_to_struct_hub(hdev);
>   if (hub) {
> + port_dev = hub->ports[portnum - 1];
> + if (port_dev && port_dev->child)
> + pm_wakeup_event(_dev->child->dev, 0);
> +
>   set_bit(portnum, hub->wakeup_bits);
>   kick_hub_wq(hub);
>   }
> @@ -3434,8 +3439,11 @@ int usb_port_resume(struct usb_device *udev, 
> pm_message_t msg)
>  
>   /* Skip the initial Clear-Suspend step for a remote wakeup */
>   status = hub_port_status(hub, port1, , );
> - if (status == 0 && !port_is_suspended(hub, portstatus))
> + if (status == 0 && !port_is_suspended(hub, portstatus)) {
> + if (portchange & USB_PORT_STAT_C_SUSPEND)
> + pm_wakeup_event(>dev, 0);
>   goto SuspendCleared;
> + }
>  
>   /* see 7.1.7.7; affects power usage, but not budgeting */
>   if (hub_is_superspeed(hub->hdev))
> 

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[PATCH V2] USB: Increment wakeup count on remote wakeup.

[Ravi Chandra Sadineni]

On chromebooks we depend on wakeup count to identify the wakeup source.
But currently USB devices do not increment the wakeup count when they
trigger the remote wake. This patch addresses the same.

Resume condition is reported differently on USB 2.0 and USB 3.0 devices.

On USB 2.0 devices, a wake capable device, if wake enabled, drives
resume signal to indicate a remote wake (USB 2.0 spec section 7.1.7.7).
The upstream facing port then sets C_PORT_SUSPEND bit and reports a
port change event (USB 2.0 spec section 11.24.2.7.2.3). Thus if a port
has resumed before driving the resume signal from the host and
C_PORT_SUSPEND is set, then the device attached to the given port might
be the reason for the last system wakeup. Increment the wakeup count for
the same.

On USB 3.0 devices, a function may signal that it wants to exit from device
suspend by sending a Function Wake Device Notification to the host (USB3.0
spec section 8.5.6.4) Thus on receiving the Function Wake, increment the
wakeup count.

Signed-off-by: Ravi Chandra Sadineni 
---
 drivers/usb/core/hcd.c |  2 ++
 drivers/usb/core/hub.c | 10 +-
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/core/hcd.c b/drivers/usb/core/hcd.c
index 777036ae63674..ee0f3ec57ce49 100644
--- a/drivers/usb/core/hcd.c
+++ b/drivers/usb/core/hcd.c
@@ -2374,7 +2374,9 @@ static void hcd_resume_work(struct work_struct *work)
 void usb_hcd_resume_root_hub (struct usb_hcd *hcd)
 {
unsigned long flags;
+   struct device *dev = >self.root_hub->dev;
 
+   pm_wakeup_event(dev, 0);
spin_lock_irqsave (_root_hub_lock, flags);
if (hcd->rh_registered) {
set_bit(HCD_FLAG_WAKEUP_PENDING, >flags);
diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index f6ea16e9f6bb9..aa9968d90a48c 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -653,12 +653,17 @@ void usb_wakeup_notification(struct usb_device *hdev,
unsigned int portnum)
 {
struct usb_hub *hub;
+   struct usb_port *port_dev;
 
if (!hdev)
return;
 
hub = usb_hub_to_struct_hub(hdev);
if (hub) {
+   port_dev = hub->ports[portnum - 1];
+   if (port_dev && port_dev->child)
+   pm_wakeup_event(_dev->child->dev, 0);
+
set_bit(portnum, hub->wakeup_bits);
kick_hub_wq(hub);
}
@@ -3434,8 +3439,11 @@ int usb_port_resume(struct usb_device *udev, 
pm_message_t msg)
 
/* Skip the initial Clear-Suspend step for a remote wakeup */
status = hub_port_status(hub, port1, , );
-   if (status == 0 && !port_is_suspended(hub, portstatus))
+   if (status == 0 && !port_is_suspended(hub, portstatus)) {
+   if (portchange & USB_PORT_STAT_C_SUSPEND)
+   pm_wakeup_event(>dev, 0);
goto SuspendCleared;
+   }
 
/* see 7.1.7.7; affects power usage, but not budgeting */
if (hub_is_superspeed(hub->hdev))
-- 
2.13.5

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