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From: Ravi Chandra Sadineni <ravisadineni@google.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Ravi Chandra Sadineni <ravisadineni@chromium.org>,
	gregkh@linuxfoundation.org,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
	chunfeng.yun@mediatek.com, johan@kernel.org,
	Arvind Yadav <arvind.yadav.cs@gmail.com>,
	Dmitry Torokhov <dtor@google.com>,
	Anton Bondarenko <anton.bondarenko.sama@gmail.com>,
	Florian Fainelli <f.fainelli@gmail.com>,
	Kees Cook <keescook@chromium.org>,
	mathias.nyman@linux.intel.com, felipe.balbi@linux.intel.com,
	Eugene Korenevsky <ekorenevsky@gmail.com>,
	peter.chen@nxp.com, joe@perches.com,
	Todd Broch <tbroch@google.com>,
	linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	Rajat Jain <rajatja@google.com>, Benson Leung <bleung@google.com>
Subject: Re: [PATCH V3] USB: Increment wakeup count on remote wakeup.
Date: Fri, 20 Apr 2018 11:12:55 -0700	[thread overview]
Message-ID: <CAOGSYL3QPu=zJJSfWuLo2bWB+AEAo53BF0TPmQCBQvQLvheLfg@mail.gmail.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1804201325430.1407-100000@iolanthe.rowland.org>

On Fri, Apr 20, 2018 at 10:29 AM, Alan Stern <stern@rowland.harvard.edu> wrote:
> On Fri, 20 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 <ravisadineni@chromium.org>
>> ---
>
> At this point you're supposed to list the differences between this
> patch and the preceding versions.

Mentioned the changes between different versions in V5. Thanks.

>
>>  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..b8024ae4fdcaa 100644
>> --- a/drivers/usb/core/hcd.c
>> +++ b/drivers/usb/core/hcd.c
>> @@ -2375,6 +2375,8 @@ void usb_hcd_resume_root_hub (struct usb_hcd *hcd)
>>  {
>>       unsigned long flags;
>>
>> +     if (hcd->rh_registered)
>> +             pm_wakeup_event(&hcd->self.root_hub->dev, 0);
>>       spin_lock_irqsave (&hcd_root_hub_lock, flags);
>>       if (hcd->rh_registered) {
>>               set_bit(HCD_FLAG_WAKEUP_PENDING, &hcd->flags);
>
> This isn't good enough.  hcd->rh_registered can change at any time;
> it is protected by the hcd_root_hub_lock spinlock.  That's why I said
> your code should be moved inside the existing "if" statement.

Sorry about this.  Fixed it now. Hope this is fine. 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(&port_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, &portstatus, &portchange);
>> -     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(&udev->dev, 0);
>>               goto SuspendCleared;
>> +     }
>>
>>       /* see 7.1.7.7; affects power usage, but not budgeting */
>>       if (hub_is_superspeed(hub->hdev))
>>
>
Thanks,
Ravi

  parent reply	other threads:[~2018-04-20 18:13 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-19  0:18 [PATCH] " Ravi Chandra Sadineni
2018-04-19  9:30 ` kbuild test robot
2018-04-19  9:33 ` kbuild test robot
2018-04-19 15:01 ` Alan Stern
2018-04-19 16:17   ` Rajat Jain
2018-04-20  0:27   ` [PATCH V2] " Ravi Chandra Sadineni
2018-04-20 14:12     ` Alan Stern
2018-04-20 17:05       ` [PATCH V3] " Ravi Chandra Sadineni
2018-04-20 17:29         ` Alan Stern
2018-04-20 17:54           ` [PATCH V4] " Ravi Chandra Sadineni
2018-04-20 18:08           ` [PATCH V5] " Ravi Chandra Sadineni
2018-04-20 18:22             ` Alan Stern
2018-04-21  8:59             ` Greg KH
2018-04-21 13:37               ` Ravi Chandra Sadineni
2018-04-20 18:12           ` Ravi Chandra Sadineni [this message]
2018-04-20 17:07       ` [PATCH V2] " Ravi Chandra Sadineni
2018-04-20  0:50   ` [PATCH] " Ravi Chandra Sadineni

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