Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Subject: Re: [PATCH v1] usb: xhci: tegra: Check padctrl interrupt presence in
 device tree
From:   Dmitry Osipenko <digetx@gmail.com>
To:     Thierry Reding <thierry.reding@gmail.com>
Cc:     Thierry Reding <treding@nvidia.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Mathias Nyman <mathias.nyman@intel.com>,
        JC Kuo <jckuo@nvidia.com>, Nicolas Chauvet <kwizart@gmail.com>,
        linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-tegra@vger.kernel.org
References: <20211021115501.14932-1-digetx@gmail.com>
 <YXFyu+Q5ifG8Au9w@orome.fritz.box>
 <5f122caa-c810-534d-b2a1-53edef313ff0@gmail.com>
Message-ID: <32694811-8768-8e77-f188-4ed1a1fb93da@gmail.com>
Date:   Thu, 21 Oct 2021 18:08:41 +0300
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.11.0
MIME-Version: 1.0
In-Reply-To: <5f122caa-c810-534d-b2a1-53edef313ff0@gmail.com>
Content-Type: text/plain; charset=utf-8
Content-Language: en-US
Content-Transfer-Encoding: 8bit
Precedence: bulk

21.10.2021 17:57, Dmitry Osipenko пишет:
> It might be wrong to disable device_may_wakeup() because it will change
> the system suspend-resume behaviour, i.e. you won't be able to resume by
> USB event, see [1].
> 
> [1]
> https://elixir.bootlin.com/linux/v5.15-rc6/source/drivers/usb/host/xhci-tegra.c#L1962
> 
> Although, I'm not sure whether this is a correct behaviour to start
> with. Previously, before the offending commit, device_wakeup was never
> enabled for tegra-xusb. Commit message doesn't explain why wakeup is now
> enabled unconditionally, wakeup checks aren't needed at all then. This
> makes no sense, please check it with JC Kuo.

Although, wakeup could be disabled via sysfs, so it makes sense. Still
it's not clear whether it's a correct behaviour to enable wakeup during
system suspend by default. If it wakes machine from suspend when USB
device is plugged/unplugged, then it's a wrong behaviour.