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Message-ID: <06343334-b3e1-004d-954e-93b3cf022079@quicinc.com>
Date: Mon, 6 Feb 2023 18:14:43 -0800
From: Elson Serrao <quic_eserrao@...cinc.com>
To: Thinh Nguyen <Thinh.Nguyen@...opsys.com>
CC: "gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
"balbi@...nel.org" <balbi@...nel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
"linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
"quic_wcheng@...cinc.com" <quic_wcheng@...cinc.com>,
"quic_jackp@...cinc.com" <quic_jackp@...cinc.com>
Subject: Re: [PATCH v3 0/5] Add function suspend/resume and remote wakeup
support
On 2/6/2023 5:24 PM, Thinh Nguyen wrote:
> Hi Elson,
>
> On Mon, Feb 06, 2023, Elson Roy Serrao wrote:
>> Changes in v3
>> - Modified rw_capable flag to reflect the gadgets capability for wakeup
>> signalling.
>> - Added a check to configure wakeup bit in bmAttributes only if gadget
>> is capable of triggering wakeup.
>> - Implemented a gadget op for composite layer to inform UDC whether device
>> is configured for remote wakeup.
>> - Added a check in __usb_gadget_wakeup() API to trigger wakeup only if the
>> device is configured for it.
>> - Cosmetic changes in dwc3_gadget_func_wakeup() API.
>>
>> Changes in v2
>> - Added a flag to indicate whether the device is remote wakeup capable.
>> - Added an async parameter to _dwc3_gadget_wakeup() API and few cosmetic
>> changes.
>> - Added flags to reflect the state of function suspend and function remote
>> wakeup to usb_function struct rather than function specific struct (f_ecm).
>> - Changed the dwc3_gadget_func__wakeup() API to run synchronously by first
>> checking the link state and then sending the device notification. Also
>> added debug log for DEVICE_NOTIFICATION generic cmd.
>> - Added changes to arm the device for remotewakeup/function remotewakeup
>> only if device is capable.
>>
>> An usb device can initate a remote wakeup and bring the link out of
>> suspend as dictated by the DEVICE_REMOTE_WAKEUP feature selector.
>> To achieve this an interface can invoke gadget_wakeup op and wait for the
>> device to come out of LPM. But the current polling based implementation
>> fails if the host takes a long time to drive the resume signaling specially
>> in high speed capable devices. Switching to an interrupt based approach is
>> more robust and efficient. This can be leveraged by enabling link status
>> change events and triggering a gadget resume when the link comes to active
>> state.
>>
>> If the device is enhanced super-speed capable, individual interfaces can
>> also be put into suspend state. An interface can be in function suspend
>> state even when the device is not in suspend state. Function suspend state
>> is retained throughout the device suspend entry and exit process.
>> A function can be put to function suspend through FUNCTION_SUSPEND feature
>> selector sent by the host. This setup packet also decides whether that
>> function is capable of initiating a function remote wakeup. When the
>> function sends a wakeup notification to the host the link must be first
>> brought to a non-U0 state and then this notification is sent.
>>
>> This change adds the infrastructure needed to support the above
>> functionalities.
>>
>> Elson Roy Serrao (5):
>> usb: gadget: Properly configure the device for remote wakeup
>> usb: dwc3: Add remote wakeup handling
>> usb: gadget: Add function wakeup support
>> usb: dwc3: Add function suspend and function wakeup support
>> usb: gadget: f_ecm: Add suspend/resume and remote wakeup support
>>
>> drivers/usb/dwc3/core.h | 5 ++
>> drivers/usb/dwc3/debug.h | 2 +
>> drivers/usb/dwc3/ep0.c | 16 ++---
>> drivers/usb/dwc3/gadget.c | 110 +++++++++++++++++++++++++++++++---
>> drivers/usb/gadget/composite.c | 50 +++++++++++++++-
>> drivers/usb/gadget/function/f_ecm.c | 68 +++++++++++++++++++++
>> drivers/usb/gadget/function/u_ether.c | 63 +++++++++++++++++++
>> drivers/usb/gadget/function/u_ether.h | 4 ++
>> drivers/usb/gadget/udc/core.c | 46 ++++++++++++++
>> drivers/usb/gadget/udc/trace.h | 5 ++
>> include/linux/usb/composite.h | 6 ++
>> include/linux/usb/gadget.h | 12 ++++
>> 12 files changed, 371 insertions(+), 16 deletions(-)
>>
>> --
>> 2.7.4
>>
>
> Hi Elson,
>
> Thanks for your patches! I provided some comments. Hopefully they can be
> merged soon.
>
> Thanks,
> Thinh
Hi Thinh
Thank you for your feedback/comments. I will address them in v4.
Regards
Elson
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