From mboxrd@z Thu Jan 1 00:00:00 1970 From: Rob Herring Subject: Re: [RFC PATCH 0/2] USB: DTS: allow suggesting busnumber for platform USB bus via DTS alias Date: Tue, 11 Dec 2018 16:42:42 -0600 Message-ID: <20181211224242.GA21950@bogus> References: <20181127165705.GA13460@lagavulin.indurad.x> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Return-path: Content-Disposition: inline In-Reply-To: <20181127165705.GA13460@lagavulin.indurad.x> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: systemd-devel-bounces@lists.freedesktop.org Sender: "systemd-devel" To: "David R. Piegdon" Cc: Mark Rutland , devicetree@vger.kernel.org, Mathias Nyman , "Gustavo A. R. Silva" , Martin Blumenstingl , Sebastian Andrzej Siewior , linux-usb@vger.kernel.org, Kay Sievers , Johan Hovold , linux-kernel@vger.kernel.org, Alan Stern , Chunfeng Yun , systemd-devel@lists.freedesktop.org, Roger Quadros List-Id: devicetree@vger.kernel.org T24gVHVlLCBOb3YgMjcsIDIwMTggYXQgMDQ6NTc6MDVQTSArMDAwMCwgRGF2aWQgUi4gUGllZ2Rv biB3cm90ZToKPiBIaSwKPiAKPiBvbiBvdXIgZW1iZWRkZWQgc3lzdGVtcyB3ZSByZWx5IG9uIHN5 c3RlbWQncyBwZXJzaXN0ZW50IG5ldGRldiBuYW1lcy4KPiBUaG9zZSBjdXJyZW50bHkgZG8gbm90 IHdvcmsgZm9yIFVTQiBuZXRkZXZzIHRoYXQgYXJlIGNvbm5lY3RlZCB0byBhCj4gcGxhdGZvcm0g VVNCIGJ1cy4KPiAKPiBJbiBodHRwczovL2dpdGh1Yi5jb20vc3lzdGVtZC9zeXN0ZW1kL3B1bGwv NzI3MyBhIHN5c3RlbWQgcGF0Y2ggd2FzCj4gc3VnZ2VzdGVkIHRoYXQgd291bGQgYWxsb3cgZXhh Y3RseSB0aGlzLCBidXQgaXQgd2FzIChyaWdodGZ1bGx5KSBzYWlkCj4gdGhhdCBudW1iZXJpbmcg b2YgdGhlc2VzIGJ1c3NlcyBpcyBub3QgZ3VhcmFudGVlZC4gSW50ZXJuYWxseSB3ZSB1c2VkCj4g dGhlIHBhdGNoIGZvciBhIHdoaWxlIG5vdywgYnV0IGV4YWN0bHkgdGhhdCBoYXMgaGFwcGVuZWQg d2l0aCBvbmUgb2Ygb3VyCj4gcGxhdGZvcm1zIGFjcm9zcyBkaWZmZXJlbnQga2VybmVsIHJldmlz aW9ucy4KPiAKPiBUaGUgZm9sbG93aW5nIGtlcm5lbCBwYXRjaGVzIGFsbG93IHN1Z2dlc3Rpbmcg YSBVU0IgYnVzbnVtYmVyIGZvciBlYWNoCj4gVVNCIHBsYXRmb3JtIGJ1cyB2aWEgYSBEVFMgYWxp YXMsIGFzIGNhbiBiZSBkb25lIHNpbWlsYXJseSBmb3IgbWFueQo+IG90aGVyIGRldmljZXMuCj4g SW4gY29tYmluYXRpb24gd2l0aCBhYm92ZSBzeXN0ZW1kIHBhdGNoLCB0aGVzZSBjaGFuZ2VzIGFs bG93IHVzZSBvZgo+IHBlcnNpc3RlbnQgbmV0ZGV2IG5hbWVzIGFsc28gb24gcGxhdGZvcm0gVVNC IGJ1c3Nlcy4KCkkgZG9uJ3QgdGhpbmsgdGhpcyBpcyBkb2luZyB3aGF0IHdhcyBzdWdnZXN0ZWQg aW4gdGhlIGxpbmsgYWJvdmUuIFRob3VnaCAKSSdtIG5vdCBmYW1pbGlhciB3aXRoIHdoYXQgQUNQ SSBwcm92aWRlcy4gVXNlcnNwYWNlIHdvdWxkIHN0aWxsIGJlIApyZWx5aW5nIG9uIHRoZSBMaW51 eCBlbnVtZXJhdGlvbiBudW1iZXJpbmcuIEhvdyB3b3VsZCB1c2Vyc3BhY2UgdGVsbCBpZiAKdGhh dCBudW1iZXJpbmcgaXMgcGVyc2lzdGVudCBvciBub3Qgb3RoZXIgdGhhbiBsb29raW5nIGF0IHRo ZSBEVCBpdHNlbGYgCih3aGljaCBpc24ndCBhIGdvb2Qgc29sdXRpb24gZWl0aGVyKT8KCkkgZG9u J3QgdW5kZXJzdGFuZCB0aG91Z2ggd2h5IHVzZXJzcGFjZSBuZWVkcyBhbnl0aGluZyBtb3JlIHRo YXQgdGhlIG1hYyAKYWRkcmVzcyBvZiBhIG5ldCBkZXZpY2UgdG8gcHJvdmlkZSBhIHBlcnNpc3Rl bnQgbmFtZS4KClJvYgpfX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19f X19fXwpzeXN0ZW1kLWRldmVsIG1haWxpbmcgbGlzdApzeXN0ZW1kLWRldmVsQGxpc3RzLmZyZWVk ZXNrdG9wLm9yZwpodHRwczovL2xpc3RzLmZyZWVkZXNrdG9wLm9yZy9tYWlsbWFuL2xpc3RpbmZv L3N5c3RlbWQtZGV2ZWwK From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_PASS, USER_AGENT_MUTT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 9453FC6783B for ; 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[24.155.109.49]) by smtp.gmail.com with ESMTPSA id g4sm8332135otp.53.2018.12.11.14.42.42 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Tue, 11 Dec 2018 14:42:42 -0800 (PST) Date: Tue, 11 Dec 2018 16:42:42 -0600 From: Rob Herring To: "David R. Piegdon" Cc: "Gustavo A. R. Silva" , Alan Stern , Chunfeng Yun , Greg Kroah-Hartman , Johan Hovold , Kay Sievers , Mark Rutland , Martin Blumenstingl , Mathias Nyman , Roger Quadros , Sebastian Andrzej Siewior , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org, systemd-devel@lists.freedesktop.org Subject: Re: [RFC PATCH 0/2] USB: DTS: allow suggesting busnumber for platform USB bus via DTS alias Message-ID: <20181211224242.GA21950@bogus> References: <20181127165705.GA13460@lagavulin.indurad.x> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20181127165705.GA13460@lagavulin.indurad.x> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Nov 27, 2018 at 04:57:05PM +0000, David R. Piegdon wrote: > Hi, > > on our embedded systems we rely on systemd's persistent netdev names. > Those currently do not work for USB netdevs that are connected to a > platform USB bus. > > In https://github.com/systemd/systemd/pull/7273 a systemd patch was > suggested that would allow exactly this, but it was (rightfully) said > that numbering of theses busses is not guaranteed. Internally we used > the patch for a while now, but exactly that has happened with one of our > platforms across different kernel revisions. > > The following kernel patches allow suggesting a USB busnumber for each > USB platform bus via a DTS alias, as can be done similarly for many > other devices. > In combination with above systemd patch, these changes allow use of > persistent netdev names also on platform USB busses. I don't think this is doing what was suggested in the link above. Though I'm not familiar with what ACPI provides. Userspace would still be relying on the Linux enumeration numbering. How would userspace tell if that numbering is persistent or not other than looking at the DT itself (which isn't a good solution either)? I don't understand though why userspace needs anything more that the mac address of a net device to provide a persistent name. Rob