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From: Heikki Krogerus <heikki.krogerus@linux.intel.com>
To: Hans de Goede <hdegoede@redhat.com>
Cc: Greg KH <gregkh@linuxfoundation.org>,
	linux-usb@vger.kernel.org, stable@vger.kernel.org
Subject: usb: typec: Registering real device entries for the muxes
Date: Tue, 2 Apr 2019 15:47:47 +0300	[thread overview]
Message-ID: <20190402124747.GH9993@kuha.fi.intel.com> (raw)

On Mon, Apr 01, 2019 at 02:45:11PM +0200, Hans de Goede wrote:
> HI,
> 
> On 01-04-19 14:40, Heikki Krogerus wrote:
> > On Mon, Apr 01, 2019 at 12:34:29PM +0200, Greg KH wrote:
> > > On Mon, Apr 01, 2019 at 01:15:53PM +0300, Heikki Krogerus wrote:
> > > > Registering real device entries (struct device) for the mode
> > > > muxes as well as for the orientation switches.
> > > > 
> > > > The Type-C mux code was deliberately attempting to avoid
> > > > creation of separate device entries for the orientation
> > > > switch and the mode switch (alternate modes) because they
> > > > are not physical devices. They are functions of a single
> > > > physical multiplexer/demultiplexer switch device.
> > > > 
> > > > Unfortunately because of the dependency we still have on the
> > > > underlying mux device driver, we had to put in hacks like
> > > > the one in the commit 3e3b81965cbf ("usb: typec: mux: Take
> > > > care of driver module reference counting") to make sure the
> > > > driver does not disappear from underneath us. Even with
> > > > those hacks we were still left with a potential NUll pointer
> > > > dereference scenario, so just creating the device entries,
> > > > and letting the core take care of the dependencies. No more
> > > > hacks needed.
> > > > 
> > > > Fixes: 3e3b81965cbf ("usb: typec: mux: Take care of driver module reference counting")
> > > > Cc: v4.19.x <stable@vger.kernel.org> # v4.19.x+
> > > > Signed-off-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
> > > 
> > > This looks good to me, nice work!
> > > 
> > > But, it would be nice if someone who has this hardware can test it to
> > > verify it does actually work :)
> > 
> > This alone does not work on Intel Cherrytrail platforms. I need to make
> > the Intel Cherrytrail MFD driver (intel_cht_int33fe.c) to use the new
> > device names that we now have for the muxes. Sorry for the mistake.
> > 
> > I'll resend this and include the needed modifications to
> > intel_cht_int33fe.c. Hans should be able to test this once I do that. I
> > hope he has time.
> 
> Yes I need to get back to the CherryTrail Type-C stuff we discussed a while
> back anyways. On which tree/branch should I test v2 of this patch(series) ?

Greg's usb-next.

thanks,

             reply	other threads:[~2019-04-02 12:47 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-02 12:47 Heikki Krogerus [this message]
  -- strict thread matches above, loose matches on Subject: below --
2019-04-03 10:29 usb: typec: Registering real device entries for the muxes Heikki Krogerus
2019-04-02  7:35 kbuild test robot
2019-04-01 12:45 Hans de Goede
2019-04-01 12:40 Heikki Krogerus
2019-04-01 10:34 Greg Kroah-Hartman
2019-04-01 10:15 Heikki Krogerus

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