From: Tony Lindgren <tony@atomide.com>
To: Bin Liu <b-liu@ti.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-usb@vger.kernel.org, linux-omap@vger.kernel.org,
Merlijn Wajer <merlijn@wizzup.org>, Pavel Machek <pavel@ucw.cz>,
Sebastian Reichel <sre@kernel.org>
Subject: Re: [PATCH] usb: musb: fix idling for suspend after disconnect interrupt
Date: Thu, 12 Dec 2019 08:09:46 -0800 [thread overview]
Message-ID: <20191212160946.GR35479@atomide.com> (raw)
In-Reply-To: <20191212160059.GI16429@iaqt7>
Hi,
* Bin Liu <b-liu@ti.com> [191212 16:02]:
> Hi Tony,
>
> Sorry for my late response.
No worries.
> On Mon, Nov 25, 2019 at 07:41:51PM -0800, Tony Lindgren wrote:
> > When disconnected as USB B-device, we sometimes get a suspend interrupt
> > after disconnect interrupt. In that case we have devctl set to 99 with
> > VBUS still valid and musb_pm_runtime_check_session() wrongly things we
> > have an active session. We have no other interrupts after disconnect
> > coming in this case at least with the omap2430 glue.
>
> I don't have an omap2430 platform to test, but its musb doesn't generate
> DISCONNECT interrupt at all when disconnected from USB host in any case?
> It is a surprise, the musb core driver expects the DISCONNECT interrupt
> after VBUS is lost and relies on it to tear down the gadget driver and
> the state machine. I am wondering how its USB is functional without the
> DISCONNECT event...
We do get DISCONNECT, but we can then get a SUSPEND after DISCONNECT
has already happened..
That will wake up musb waiting for further interrupts thinking it's
connected. But after that there are no more interrupts as the cable
is disconnected so we need to poll the status again.
If we see SUSPEND before DISCONNECT, then things idle fine.
Regards,
Tony
next prev parent reply other threads:[~2019-12-12 16:09 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-26 3:41 [PATCH] usb: musb: fix idling for suspend after disconnect interrupt Tony Lindgren
2019-11-26 10:20 ` Sergei Shtylyov
2019-11-26 17:45 ` Tony Lindgren
2019-12-12 17:21 ` Bin Liu
2019-12-12 17:26 ` Tony Lindgren
2019-12-12 16:00 ` Bin Liu
2019-12-12 16:09 ` Tony Lindgren [this message]
2019-12-12 17:08 ` Bin Liu
2019-12-12 17:15 ` Tony Lindgren
2020-10-27 4:55 ` Bhushan Shah
2020-10-27 6:17 ` Tony Lindgren
2020-10-27 7:59 ` Bhushan Shah
2020-10-28 8:42 ` Tony Lindgren
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