From: Oliver Neukum <oneukum@suse.com>
To: Johan Hovold <johan@kernel.org>
Cc: Loic Poulain <loic.poulain@linaro.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Karoly Pados <pados@pados.hu>,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
Subject: [v2] USB: serial: cp210x: Fix GPIO in autosuspend
Date: Tue, 19 Mar 2019 12:15:06 +0100 [thread overview]
Message-ID: <1552994106.14757.34.camel@suse.com> (raw)
On Di, 2019-03-19 at 11:36 +0100, Johan Hovold wrote:
> On Mon, Feb 18, 2019 at 10:17:12AM +0100, Oliver Neukum wrote:
> > On So, 2019-02-17 at 18:59 +0100, Karoly Pados wrote:
> > > Current GPIO code in cp210x fails to take USB autosuspend into account,
> > > making it practically impossible to use GPIOs with autosuspend enabled
> > > without user configuration. Fix this like for ftdi_sio in a previous patch.
> > > Tested on a CP2102N.
> > your patch is looking good to me, but I am afraid there are issues.
> > How do the GPIO lines on the device interact with USB reset and system
> > suspend?
>
> What was your concern here, Oliver?
If you have a device resetting or losing power (for reset_resume) the
GPIO lines will revert to the default. But that change is not reported
to user space, is it?
So the original patch is correct, but there are more situations rather
than suspend which could trigger the problem.
Regards
Oliver
WARNING: multiple messages have this Message-ID (diff)
From: Oliver Neukum <oneukum@suse.com>
To: Johan Hovold <johan@kernel.org>
Cc: Loic Poulain <loic.poulain@linaro.org>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Karoly Pados <pados@pados.hu>,
linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org
Subject: Re: [PATCH v2] USB: serial: cp210x: Fix GPIO in autosuspend
Date: Tue, 19 Mar 2019 12:15:06 +0100 [thread overview]
Message-ID: <1552994106.14757.34.camel@suse.com> (raw)
In-Reply-To: <20190319103659.GA3178@localhost>
On Di, 2019-03-19 at 11:36 +0100, Johan Hovold wrote:
> On Mon, Feb 18, 2019 at 10:17:12AM +0100, Oliver Neukum wrote:
> > On So, 2019-02-17 at 18:59 +0100, Karoly Pados wrote:
> > > Current GPIO code in cp210x fails to take USB autosuspend into account,
> > > making it practically impossible to use GPIOs with autosuspend enabled
> > > without user configuration. Fix this like for ftdi_sio in a previous patch.
> > > Tested on a CP2102N.
> > your patch is looking good to me, but I am afraid there are issues.
> > How do the GPIO lines on the device interact with USB reset and system
> > suspend?
>
> What was your concern here, Oliver?
If you have a device resetting or losing power (for reset_resume) the
GPIO lines will revert to the default. But that change is not reported
to user space, is it?
So the original patch is correct, but there are more situations rather
than suspend which could trigger the problem.
Regards
Oliver
next reply other threads:[~2019-03-19 11:15 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-19 11:15 Oliver Neukum [this message]
2019-03-19 11:15 ` [PATCH v2] USB: serial: cp210x: Fix GPIO in autosuspend Oliver Neukum
-- strict thread matches above, loose matches on Subject: below --
2019-03-20 9:11 [v2] " Johan Hovold
2019-03-20 9:11 ` [PATCH v2] " Johan Hovold
2019-03-19 17:19 [v2] " Karoly Pados
2019-03-19 17:19 ` [PATCH v2] " Karoly Pados
2019-03-19 17:12 [v2] " Karoly Pados
2019-03-19 17:12 ` [PATCH v2] " Karoly Pados
2019-03-19 13:14 [v2] " Johan Hovold
2019-03-19 13:14 ` [PATCH v2] " Johan Hovold
2019-03-19 10:36 [v2] " Johan Hovold
2019-03-19 10:36 ` [PATCH v2] " Johan Hovold
2019-02-20 9:23 [v2] " Johan Hovold
2019-02-20 9:23 ` [PATCH v2] " Johan Hovold
2019-02-18 9:17 [v2] " Oliver Neukum
2019-02-18 9:17 ` [PATCH v2] " Oliver Neukum
2019-02-17 17:59 [v2] " Karoly Pados
2019-02-17 17:59 ` [PATCH v2] " Karoly Pados
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