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From: Bin Liu <b-liu@ti.com>
To: Johan Hovold <johan@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Alan Stern <stern@rowland.harvard.edu>,
	Arnd Bergmann <arnd@arndb.de>,
	Kishon Vijay Abraham I <kishon@ti.com>,
	Martin Blumenstingl <martin.blumenstingl@googlemail.com>,
	<linux-usb@vger.kernel.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/3] USB: musb: dsps: phy fix and DT-topology support
Date: Wed, 18 Apr 2018 13:56:13 -0500	[thread overview]
Message-ID: <20180418185613.GH14921@uda0271908> (raw)
In-Reply-To: <20180418184640.GJ9198@localhost>

On Wed, Apr 18, 2018 at 08:46:40PM +0200, Johan Hovold wrote:
> On Wed, Apr 18, 2018 at 11:20:15AM -0500, Bin Liu wrote:
> > Johan,
> > 
> > On Fri, Apr 13, 2018 at 05:15:02PM +0200, Johan Hovold wrote:
> > > I've been carrying a patch out-of-tree since my work on improving the
> > > USB device-tree support which is needed to be able to describe USB
> > > topologies for musb based controllers.
> > > 
> > > This patch, which associates the platform controller device with the
> > > glue device device-tree node, did not play well with the recent changes
> > > which added generic phy support to USB core however.
> > > 
> > > Like the recent dwc2 regression fixed by Arnd after the device-tree
> > > #phy-cell changes, the generic phy code in USB core can now also fail
> > > indefinitly with -EPROBE_DEFER when the controller uses a legacy USB
> > > phy.
> > > 
> > > The second patch addresses this for musb, which handles its own (legacy
> > > and generic) phys, but something more may possibly now be needed for
> > > other platforms with legacy phys.
> > > 
> > > In the process of debugging this, I stumbled over another issue which
> > > caused the dsps legacy phy init two be called twice on every probe and
> > > which is fixed by the first patch.
> > > 
> > > Johan
> > > 
> > > 
> > > Johan Hovold (3):
> > >   USB: musb: dsps: drop duplicate phy initialisation
> > >   USB: musb: host: prevent core phy initialisation
> > 
> > Are the two bugs only affecting you with your out-of-tree patch? It
> > seems don't have any functional impact for me. I need to make a decision
> > if these two patches need to go to the stable trees...
> 
> The first bug is independent of the third patch (the "out-of-tree"
> patch), but as Uwe also noted it seems to be mostly benign since it took
> two years for it to be discovered. For that reason, and to minimise the
> risk of any stable regressions, I did not mark it for stable.
> 
> The second fix is really only needed with the third of_node patch since
> I don't think any of the glue drivers propagates the device-tree node in
> this way currently. Hence it could also wait for 3.18, and it is in any
> case not stable material as the generic-phy support in USB core is new
> in 3.17.

Great, thanks for confirming. I will not send them for stable trees.

> 
> Note that other host controllers may have a device-tree node with
> associated legacy-phys however and that this could now lead to similar
> problems starting with 3.17.

regards,
-Bin.


  reply	other threads:[~2018-04-18 18:56 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-04-13 15:15 Johan Hovold
2018-04-13 15:15 ` [PATCH 1/3] USB: musb: dsps: drop duplicate phy initialisation Johan Hovold
2018-04-13 18:45   ` Uwe Kleine-König
2018-04-13 15:15 ` [PATCH 2/3] USB: musb: host: prevent core " Johan Hovold
2018-04-13 15:15 ` [PATCH 3/3] USB: musb: dsps: propagate device-tree node Johan Hovold
2018-04-16 20:03   ` Bin Liu
2018-04-17  7:07     ` Johan Hovold
2018-04-18 16:20 ` [PATCH 0/3] USB: musb: dsps: phy fix and DT-topology support Bin Liu
2018-04-18 18:46   ` Johan Hovold
2018-04-18 18:56     ` Bin Liu [this message]
2018-04-18 19:18 ` Martin Blumenstingl
2018-04-19  7:43   ` Johan Hovold
2018-04-19 21:54     ` Martin Blumenstingl

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