From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Serge Semin <fancer.lancer@gmail.com>
Cc: Krzysztof Kozlowski <krzk@kernel.org>,
Rob Herring <robh+dt@kernel.org>,
Serge Semin <Sergey.Semin@baikalelectronics.ru>,
John Stultz <john.stultz@linaro.org>,
Felipe Balbi <balbi@kernel.org>,
Florian Fainelli <f.fainelli@gmail.com>,
Andy Gross <agross@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
<devicetree@vger.kernel.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
Linux USB List <linux-usb@vger.kernel.org>,
lkml <linux-kernel@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
Amit Pundir <amit.pundir@linaro.org>
Subject: Re: [PATCH 29/29] arm64: dts: qcom: Harmonize DWC USB3 DT nodes name
Date: Wed, 21 Jul 2021 12:29:11 +0200 [thread overview]
Message-ID: <YPf29+ewbrYgHxRP@kroah.com> (raw)
In-Reply-To: <20210721100220.ddfxwugivsndsedv@mobilestation>
On Wed, Jul 21, 2021 at 01:02:20PM +0300, Serge Semin wrote:
> Hi Greg,
> @Krzysztof, @Rob, please join the discussion so to finally get done
> with the concerned issue.
>
> On Wed, Jul 21, 2021 at 09:38:54AM +0200, Greg Kroah-Hartman wrote:
> > On Wed, Jul 14, 2021 at 03:48:07PM +0300, Serge Semin wrote:
> > > Hello John,
> > >
> > > On Tue, Jul 13, 2021 at 05:07:00PM -0700, John Stultz wrote:
> > > > On Tue, Oct 20, 2020 at 5:10 AM Serge Semin
> > > > <Sergey.Semin@baikalelectronics.ru> wrote:
> > > > >
> > > > > In accordance with the DWC USB3 bindings the corresponding node
> > > > > name is suppose to comply with the Generic USB HCD DT schema, which
> > > > > requires the USB nodes to have the name acceptable by the regexp:
> > > > > "^usb(@.*)?" . Make sure the "snps,dwc3"-compatible nodes are correctly
> > > > > named.
> > > > >
> > > > > Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
> > > >
> > >
> > > > I know folks like to ignore this, but this patch breaks AOSP on db845c. :(
> > >
> > > Sorry to hear that. Alas there is no much can be done about it.
> >
> > Yes there is, we can revert the change. We do not break existing
> > configurations, sorry.
>
> By reverting this patch we'll get back to the broken dt-bindings
> since it won't comply to the current USB DT-nodes requirements
> which at this state well describe the latest DT spec:
> https://github.com/devicetree-org/devicetree-specification/releases/tag/v0.3
> Thus the dtbs_check will fail for these nodes.
>
> Originally this whole patchset was connected with finally getting the
> DT-node names in order to comply with the standard requirement and it
> was successful mostly except a few patches which still haven't been
> merged in.
>
> Anyway @Krzysztof has already responded to the complain regarding this
> issue here:
> https://lore.kernel.org/lkml/20201221210423.GA2504@kozik-lap/
> but noone cared to respond on his reasonable questions in order to
> get to a suitable solution for everyone. Instead we are
> getting another email with the same request to revert the changes.
> Here is the quote from the Krzysztof email so we could continue the
> discussion:
>
> On Mon, 21 Dec 2020 13:04:27 -0800 (PST), Krzysztof Kozlowski <krzk@kernel.org> wrote:
> > On Mon, Dec 21, 2020 at 12:24:11PM -0800, John Stultz wrote:
> > > On Sat, Dec 19, 2020 at 3:06 AM Krzysztof Kozlowski <krzk@kernel.org> wrote:
> > > > ...
> > > >
> > > > The node names are not part of an ABI, are they? I expect only
> > > > compatibles and properties to be stable. If user-space looks for
> > > > something by name, it's a user-space's mistake. Not mentioning that you
> > > > also look for specific address... Imagine remapping of addresses with
> > > > ranges (for whatever reason) - AOSP also would be broken? Addresses are
> > > > definitely not an ABI.
> > >
> > > Though that is how it's exported through sysfs.
> >
> > The ABI is the format of sysfs file for example in /sys/devices. However
> > the ABI is not the exact address or node name of each device.
> >
> > > In AOSP it is then used to setup the configfs gadget by writing that
> > > value into /config/usb_gadget/g1/UDC.
> > >
> > > Given there may be multiple controllers on a device, or even if its
> > > just one and the dummy hcd driver is enabled, I'm not sure how folks
> > > reference the "right" one without the node name?
> >
> > I think it is the same type of problem as for all other subsystems, e.g.
> > mmc, hwmon/iio. They usually solve it either with aliases or with
> > special property with the name/label.
> >
> > > I understand the fuzziness with sysfs ABI, and I get that having
> > > consistent naming is important, but like the eth0 -> enp3s0 changes,
> > > it seems like this is going to break things.
> >
> > One could argue whether interface name is or is not ABI. But please tell
> > me how the address of a device in one's representation (for example DT)
> > is a part of a stable interface?
> >
> > > Greg? Is there some better way AOSP should be doing this?
> >
> > If you need to find specific device, maybe go through the given bus and
> > check compatibles?
> >
> > Best regards,
> > Krzysztof
>
> So the main question is how is the DT-node really connected with ABI
> and is supposed to be stable in that concern?
>
> As I see it even if it affects the configfs node name, then we may
> either need to break that connection and somehow deliver DT-node-name
> independent interface to the user-space or we have no choice but to
> export the node with an updated name and ask of user-space to deal
> with it. In both suggested cases the DT-node name will still conform
> to the USB-node name DT spec. Currently we are at the second one.
I really do not care what you all decide on, but you CAN NOT break
existing working systems, sorry. That is why I have reverted this
change in my tree and will send it to Linus soon.
thanks,
greg k-h
next prev parent reply other threads:[~2021-07-21 10:42 UTC|newest]
Thread overview: 110+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-20 11:59 [PATCH 00/29] dt-bindings: usb: Harmonize xHCI/EHCI/OHCI/DWC3 nodes name Serge Semin
2020-10-20 11:59 ` [PATCH 01/29] usb: dwc3: Discard synopsys,dwc3 compatibility string Serge Semin
2020-10-20 12:15 ` Andy Shevchenko
2020-10-20 12:28 ` Krzysztof Kozlowski
2020-10-20 12:33 ` Serge Semin
2020-10-20 12:27 ` Felipe Balbi
2020-10-20 11:59 ` [PATCH 02/29] arm: dts: keystone: Correct DWC USB3 compatible string Serge Semin
2020-10-20 12:30 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 03/29] arm: dts: am437x: " Serge Semin
2020-10-20 12:31 ` Krzysztof Kozlowski
2020-11-10 13:17 ` Tony Lindgren
2020-10-20 11:59 ` [PATCH 04/29] arm: dts: exynos: " Serge Semin
2020-10-26 18:55 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 05/29] arm64: dts: amlogic: meson-g12: Set FL-adj property value Serge Semin
2020-10-20 12:34 ` Krzysztof Kozlowski
2020-10-20 12:44 ` Serge Semin
2020-10-20 12:46 ` Krzysztof Kozlowski
2020-10-20 13:06 ` Neil Armstrong
2020-10-20 19:38 ` Martin Blumenstingl
2020-10-20 11:59 ` [PATCH 06/29] arc: dts: Harmonize EHCI/OHCI DT nodes name Serge Semin
2020-10-20 12:35 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 07/29] arm: dts: bcm53x: " Serge Semin
2020-10-20 12:34 ` Krzysztof Kozlowski
2020-10-22 20:43 ` Florian Fainelli
2020-10-20 11:59 ` [PATCH 08/29] arm: dts: stm32: " Serge Semin
2020-10-20 12:36 ` Krzysztof Kozlowski
2020-11-09 10:43 ` Alexandre Torgue
2020-10-20 11:59 ` [PATCH 09/29] arm: dts: hisi-x5hd2: " Serge Semin
2020-10-20 12:36 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 10/29] arm: dts: lpc18xx: " Serge Semin
2020-10-20 12:37 ` Krzysztof Kozlowski
2020-10-21 19:02 ` Vladimir Zapolskiy
2020-10-20 11:59 ` [PATCH 11/29] arm64: dts: hisi: " Serge Semin
2020-10-20 12:37 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 12/29] mips: dts: jz47x: " Serge Semin
2020-10-20 12:40 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 13/29] mips: dts: sead3: " Serge Semin
2020-10-20 12:37 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 14/29] mips: dts: ralink: mt7628a: " Serge Semin
2020-10-20 12:38 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 15/29] powerpc: dts: akebono: " Serge Semin
2020-10-20 12:38 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 16/29] arm: dts: bcm5301x: Harmonize xHCI " Serge Semin
2020-10-20 12:38 ` Krzysztof Kozlowski
2020-10-22 20:44 ` Florian Fainelli
2020-10-20 11:59 ` [PATCH 17/29] arm64: dts: marvell: cp11x: " Serge Semin
2020-10-20 12:40 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 18/29] arm: dts: marvell: armada-375: Harmonize DWC USB3 " Serge Semin
2020-10-20 12:43 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 19/29] arm: dts: exynos: " Serge Semin
2020-10-26 18:56 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 20/29] arm: dts: keystone: " Serge Semin
2020-10-20 12:41 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 21/29] arm: dts: ls1021a: " Serge Semin
2020-10-20 12:46 ` Krzysztof Kozlowski
2020-11-01 7:37 ` Shawn Guo
2020-10-20 11:59 ` [PATCH 22/29] arm: dts: omap5: " Serge Semin
2020-10-20 12:41 ` Krzysztof Kozlowski
2020-11-10 13:18 ` Tony Lindgren
2020-10-20 11:59 ` [PATCH 23/29] arm: dts: stih407-family: " Serge Semin
2020-10-20 12:41 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 24/29] arm64: dts: allwinner: h6: " Serge Semin
2020-10-20 12:42 ` Krzysztof Kozlowski
2020-10-22 16:13 ` Maxime Ripard
2020-10-20 11:59 ` [PATCH 25/29] arm64: dts: apm: " Serge Semin
2020-10-20 12:42 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 26/29] arm64: dts: exynos: " Serge Semin
2020-10-20 12:43 ` Krzysztof Kozlowski
2020-10-22 11:25 ` Serge Semin
2020-10-26 18:57 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 27/29] arm64: dts: layerscape: " Serge Semin
2020-10-20 12:47 ` Krzysztof Kozlowski
2020-11-01 7:37 ` Shawn Guo
2020-10-20 11:59 ` [PATCH 28/29] arm64: dts: hi3660: " Serge Semin
2020-10-20 12:44 ` Krzysztof Kozlowski
2020-10-20 11:59 ` [PATCH 29/29] arm64: dts: qcom: " Serge Semin
2020-10-20 12:44 ` Krzysztof Kozlowski
2020-11-02 7:34 ` Jun Li
2020-11-03 23:23 ` Bjorn Andersson
2020-11-10 12:12 ` Serge Semin
2021-07-14 0:07 ` John Stultz
2021-07-14 2:27 ` Bjorn Andersson
2021-07-21 7:39 ` Greg Kroah-Hartman
2021-07-14 12:48 ` Serge Semin
2021-07-14 14:59 ` Bjorn Andersson
2021-07-21 7:38 ` Greg Kroah-Hartman
2021-07-21 10:02 ` Serge Semin
2021-07-21 10:29 ` Greg Kroah-Hartman [this message]
2021-07-21 10:45 ` Krzysztof Kozlowski
2021-07-21 11:02 ` Greg Kroah-Hartman
2021-07-21 11:10 ` Krzysztof Kozlowski
2021-07-21 11:25 ` Serge Semin
2021-07-21 18:08 ` John Stultz
2021-07-22 18:12 ` Serge Semin
2021-07-22 19:17 ` Bjorn Andersson
2021-07-22 20:09 ` John Stultz
2021-07-22 22:09 ` Serge Semin
2021-08-14 1:06 ` John Stultz
2021-08-15 19:46 ` Serge Semin
2021-08-18 3:44 ` Bjorn Andersson
2021-08-19 11:03 ` Serge Semin
2021-07-22 21:54 ` Serge Semin
2021-07-23 8:17 ` Greg Kroah-Hartman
2021-07-21 20:09 ` Bjorn Andersson
2021-07-23 8:18 ` Greg Kroah-Hartman
2021-07-23 14:34 ` Bjorn Andersson
2021-07-23 15:54 ` Greg Kroah-Hartman
2021-07-23 19:54 ` Bjorn Andersson
2021-07-24 7:50 ` Greg Kroah-Hartman
2021-07-21 7:37 ` Greg Kroah-Hartman
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