From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [v2,1/2] USB: serial: ark3116: Remove unused TIOCSSERIAL ioctl case. From: Johan Hovold Message-Id: <20180108152858.GH11344@localhost> Date: Mon, 8 Jan 2018 16:28:58 +0100 To: Oliver Neukum Cc: Mikhail Zaytsev , Johan Hovold , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org List-ID: T24gTW9uLCBKYW4gMDgsIDIwMTggYXQgMTE6MzM6MzJBTSArMDEwMCwgT2xpdmVyIE5ldWt1bSB3 cm90ZToKPiBBbSBTYW1zdGFnLCBkZW4gMDYuMDEuMjAxOCwgMjA6MTQgKzAzMDAgc2NocmllYiBN aWtoYWlsIFpheXRzZXY6Cj4gPiBUaGUgcGF0Y2ggcmVtb3ZlcyB1bnVzZWQgVElPQ1NTRVJJQUwg aW9jdGwgY2FzZSBhbmQgYWRkcyB0aGUgZGVmYXVsdCBibG9jawo+ID4gdG8gdGhlIHN3aXRjaC4g VGhpcyB3aWxsIG1ha2UgdGhlIGlvY3RsIHJldHVybiAtRU5PVFRZIHRvIHVzZXIgc3BhY2UgKGUu Zy4KPiA+IHNldHNlcmlhbCksIGJlY2F1c2UgVElPQ1NTRVJJQUwgcmVhbGx5IGlzbid0IHN1cHBv cnRlZCBmb3IgdGhlc2UgZGV2aWNlcwo+ID4gY3VycmVudGx5Lgo+IAo+IEhpLAo+IAo+IHRoaXMg d2lsbCBicmVhayBzb2Z0d2FyZSB0aGF0IGlzIG5vdyBydW5uaW5nIG9uIHRoZXNlIGRldmljZXMs Cj4gd29uJ3QgaXQ/IERvIHlvdSBrbm93IHdoeSB0aG9zZSBkZXZpY2VzIGJhc2ljYWxseSBpZ25v cmUgdGhlCj4gaW9jdGw/CgpZZWFoLCB0aGF0IHdhcyBteSBpbml0aWFsIHJlYWN0aW9ucyBhcyB3 ZWxsLCBidXQgdGhlbiBhZ2FpbiwgYW55IHNhbmUKdXNlciBzcGFjZSBjYW5ub3QgcmVseSBvbiB0 aGVzZSBpb2N0bCBiZWluZyBpbXBsZW1lbnRlZCBmb3IgYWxsIHR0eQpkZXZpY2VzLgoKSSBkaWQg c29tZSBkaWdnaW5nIG5vdyBhbmQgdGhlc2UgKGR1bW15KSBpb2N0bCBpbXBsZW1lbnRhdGlvbnMg d2hlcmUKYWRkZWQgYnkgY29tbWl0IDJmNDMwYjRiYmFlNyAoIlVTQjogYXJrMzExNjogQWRkIFRJ T0NHU0VSSUFMIGFuZApUSU9DU1NFUklBTCBpb2N0bCBjYWxscy4iKSBiYWNrIGluIDIwMDYuICBU aGlzIGluIHR1cm4gYXBwZWFycyB0byBoYXZlCmJlZW4gdHJpZ2dlcmVkIGJ5IGEgY2hhbmdlIGlu IGEgdXNlciBzcGFjZSB0b29sLCB3dmRpYWwsIHdoaWNoIHN0YXJ0ZWQKZXJyb3Jpbmcgb3V0IGlm IGVpdGhlciB3YXMgbWlzc2luZy4KCkkgZm91bmQgYSBjb3VwbGUgb2YgYnVnIHJlcG9ydHMgYWJv dXQgdGhhdCB0aHJvdWdoIGdvb2dsZSwgYW5kIGxvb2tpbmcKYXQgdGhlIHd2c3RyZWFtcyAobGli cmFyeSkgY29kZSBub3csIGl0IGxvb2tzIGxpa2UgdGhlIGlzc3VlIGhhcyBpbmRlZWQKYmVlbiBy ZXNvbHZlZCBieSBoYW5kbGluZyBlcnJvcnMgbW9yZSBncmFjZWZ1bGx5IChlLmcuIGp1c3QgbG9n Z2luZwp0aGVtKS4KClNvIEknbSB3aWxsaW5nIHRvIGdpdmUgdGhpcyBhIHRyeSwgYW5kIGlmIGFu eW9uZSBjb21wbGFpbnMgbGF0ZXIgd2UgYWRkCmJhY2sgKG9yIGltcGxlbWVudCkgVElPQ1NTRVJJ QUwuCgpTb3VuZHMgcmVhc29uYWJsZT8KClRoYW5rcywKSm9oYW4KLS0tClRvIHVuc3Vic2NyaWJl IGZyb20gdGhpcyBsaXN0OiBzZW5kIHRoZSBsaW5lICJ1bnN1YnNjcmliZSBsaW51eC11c2IiIGlu CnRoZSBib2R5IG9mIGEgbWVzc2FnZSB0byBtYWpvcmRvbW9Admdlci5rZXJuZWwub3JnCk1vcmUg bWFqb3Jkb21vIGluZm8gYXQgIGh0dHA6Ly92Z2VyLmtlcm5lbC5vcmcvbWFqb3Jkb21vLWluZm8u aHRtbAo= From mboxrd@z Thu Jan 1 00:00:00 1970 Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933880AbeAHP3C (ORCPT + 1 other); Mon, 8 Jan 2018 10:29:02 -0500 Received: from mail-lf0-f42.google.com ([209.85.215.42]:42054 "EHLO mail-lf0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933081AbeAHP3A (ORCPT ); Mon, 8 Jan 2018 10:29:00 -0500 X-Google-Smtp-Source: ACJfBou1i68Tuc93pLkZYNPqpDP5fjpNZ736yDmQxOSTjSKDXmuHLRrFgCn/etUTsOM1XvXU8bWLAQ== Date: Mon, 8 Jan 2018 16:28:58 +0100 From: Johan Hovold To: Oliver Neukum Cc: Mikhail Zaytsev , Johan Hovold , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, linux-usb@vger.kernel.org Subject: Re: [PATCH v2 1/2] USB: serial: ark3116: Remove unused TIOCSSERIAL ioctl case. Message-ID: <20180108152858.GH11344@localhost> References: <20180106200809.41cdd723@debian> <20180106201402.03d2ac88@debian> <1515407612.29712.1.camel@suse.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1515407612.29712.1.camel@suse.com> User-Agent: Mutt/1.7.2 (2016-11-26) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Return-Path: On Mon, Jan 08, 2018 at 11:33:32AM +0100, Oliver Neukum wrote: > Am Samstag, den 06.01.2018, 20:14 +0300 schrieb Mikhail Zaytsev: > > The patch removes unused TIOCSSERIAL ioctl case and adds the default block > > to the switch. This will make the ioctl return -ENOTTY to user space (e.g. > > setserial), because TIOCSSERIAL really isn't supported for these devices > > currently. > > Hi, > > this will break software that is now running on these devices, > won't it? Do you know why those devices basically ignore the > ioctl? Yeah, that was my initial reactions as well, but then again, any sane user space cannot rely on these ioctl being implemented for all tty devices. I did some digging now and these (dummy) ioctl implementations where added by commit 2f430b4bbae7 ("USB: ark3116: Add TIOCGSERIAL and TIOCSSERIAL ioctl calls.") back in 2006. This in turn appears to have been triggered by a change in a user space tool, wvdial, which started erroring out if either was missing. I found a couple of bug reports about that through google, and looking at the wvstreams (library) code now, it looks like the issue has indeed been resolved by handling errors more gracefully (e.g. just logging them). So I'm willing to give this a try, and if anyone complains later we add back (or implement) TIOCSSERIAL. Sounds reasonable? Thanks, Johan