linux-kernel - RE: [PATCH] USB4/TBT device routers should wake up during S0ix when something gets connected/disconnected or a DP monitor gets plugged in

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Date:   Wed, 23 Mar 2022 18:11:03 +0000
From:   "Khandelwal, Rajat" <rajat.khandelwal@...el.com>
To:     "mika.westerberg@...ux.intel.com" <mika.westerberg@...ux.intel.com>,
        "bleung@...gle.com" <bleung@...gle.com>
CC:     "Malani, Prashant" <pmalani@...gle.com>,
        "jthies@...gle.com" <jthies@...gle.com>,
        "Rao, Abhijeet" <abhijeet.rao@...el.com>,
        "Regupathy, Rajaram" <rajaram.regupathy@...el.com>,
        "linux-usb@...r.kernel.org" <linux-usb@...r.kernel.org>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: RE: [PATCH] USB4/TBT device routers should wake up during S0ix when
 something gets connected/disconnected or a DP monitor gets plugged in

@bleung@...gle.com
The original bug only targets DP plugins. Should we keep connect/disconnect flows also in loop? As Mika once told me, if the lid of the DUT is closed, and the USB4/TBT device is plugged out/in, the DUT shouldn't wake up as it will cause unnecessary consumption of energy. 
Please confirm if only DP hotplugs in S0ix for waking are required.

Thanks
Rajat

-----Original Message-----
From: mika.westerberg@...ux.intel.com <mika.westerberg@...ux.intel.com> 
Sent: Wednesday, March 23, 2022 4:01 PM
To: Khandelwal, Rajat <rajat.khandelwal@...el.com>
Cc: bleung@...gle.com; Malani, Prashant <pmalani@...gle.com>; jthies@...gle.com; Rao, Abhijeet <abhijeet.rao@...el.com>; Regupathy, Rajaram <rajaram.regupathy@...el.com>; linux-usb@...r.kernel.org; linux-kernel@...r.kernel.org
Subject: Re: [PATCH] USB4/TBT device routers should wake up during S0ix when something gets connected/disconnected or a DP monitor gets plugged in

Hi,

If you want it to be woken up when something is plugged to the USB4 port then I suggest to add this to the "wakeup" capability of the usb4_port itself (see drivers/thunderbolt/usb4_port.c). And make it disabled by default too.

On Wed, Mar 23, 2022 at 10:26:37AM +0000, Khandelwal, Rajat wrote:
> +Mika
> @Malani, Prashant @bleung@...gle.com This is the patch which fixes the partner issue. Kindly escalate your thoughts. 
> 
> Thanks
> Rajat
> 
> -----Original Message-----
> From: Khandelwal, Rajat <rajat.khandelwal@...el.com>
> Sent: Wednesday, March 23, 2022 3:48 PM
> To: mika.westerberg@...ux.intel.com
> Cc: Khandelwal, Rajat <rajat.khandelwal@...el.com>; bleung@...gle.com; 
> jthies@...gle.com; Malani, Prashant <pmalani@...gle.com>; Rao, 
> Abhijeet <abhijeet.rao@...el.com>; Regupathy, Rajaram 
> <rajaram.regupathy@...el.com>; linux-usb@...r.kernel.org; 
> linux-kernel@...r.kernel.org
> Subject: [PATCH] USB4/TBT device routers should wake up during S0ix 
> when something gets connected/disconnected or a DP monitor gets 
> plugged in
> 
> Device routers don't wake up during S0ix when something is plugged in/out or if a DP monitor gets connected. This causes the linux device to not wake up during S0ix cycling as the host router didn't wake up because the device router didn't. This patch adds a new functionality to linux.
> 
> Signed-off-by: Rajat-Khandelwal <rajat.khandelwal@...el.com>
> ---
>  drivers/thunderbolt/switch.c | 4 +---
>  1 file changed, 1 insertion(+), 3 deletions(-)
> 
> diff --git a/drivers/thunderbolt/switch.c 
> b/drivers/thunderbolt/switch.c index d026e305fe5d..4f8056724aa4 100644
> --- a/drivers/thunderbolt/switch.c
> +++ b/drivers/thunderbolt/switch.c
> @@ -3067,13 +3067,11 @@ void tb_switch_suspend(struct tb_switch *sw, bool runtime)
>  			tb_switch_suspend(port->remote->sw, runtime);
>  	}
>  
> -	if (runtime) {
> +	if (runtime || device_may_wakeup(&sw->dev)) {
>  		/* Trigger wake when something is plugged in/out */
>  		flags |= TB_WAKE_ON_CONNECT | TB_WAKE_ON_DISCONNECT;
>  		flags |= TB_WAKE_ON_USB4;
>  		flags |= TB_WAKE_ON_USB3 | TB_WAKE_ON_PCIE | TB_WAKE_ON_DP;
> -	} else if (device_may_wakeup(&sw->dev)) {
> -		flags |= TB_WAKE_ON_USB4 | TB_WAKE_ON_USB3 | TB_WAKE_ON_PCIE;
>  	}
>  
>  	tb_switch_set_wake(sw, flags);
> --
> 2.17.1