From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from out2-smtp.messagingengine.com ([66.111.4.26]:37389 "EHLO out2-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751845AbbIPL0q (ORCPT ); Wed, 16 Sep 2015 07:26:46 -0400 Received: from compute1.internal (compute1.nyi.internal [10.202.2.41]) by mailout.nyi.internal (Postfix) with ESMTP id 677F1209CC for ; Wed, 16 Sep 2015 07:26:46 -0400 (EDT) Subject: Re: [PATCH 3.12 16/33] isdn/gigaset: reset tty->receive_room when attaching ser_gigaset To: Peter Hurley References: <350624fa32cb152bfec51f236b0b62b8d480a05a.1442326825.git.jslaby@suse.cz> <4a187391f4c7d54b9c07eed08de48ffd6e0a3f20.1442326825.git.jslaby@suse.cz> <55F8B9D9.5060201@imap.cc> Cc: Jiri Slaby , "stable@vger.kernel.org" , Linux kernel mailing list , "David S. Miller" From: Tilman Schmidt Message-ID: <55F951EA.1060001@imap.cc> Date: Wed, 16 Sep 2015 13:26:34 +0200 MIME-Version: 1.0 In-Reply-To: Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="7hQMNKUtdJC8VPm56GwHbkU9DWBnXMOGE" Sender: stable-owner@vger.kernel.org List-ID: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --7hQMNKUtdJC8VPm56GwHbkU9DWBnXMOGE Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Am 16.09.2015 um 03:18 schrieb Peter Hurley: > On Tue, Sep 15, 2015 at 8:37 PM, Tilman Schmidt wrote:= >> Am 16.09.2015 um 01:08 schrieb Peter Hurley: >>> On Tue, Sep 15, 2015 at 10:22 AM, Jiri Slaby wrote: >>> >>> From: Tilman Schmidt >>> >>> 3.12-stable review patch. If anyone has any objections, please l= et >>> me know. >>> >>> =3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D=3D >>> >>> [ Upstream commit fd98e9419d8d622a4de91f76b306af6aa627aa9c ] >>> >>> Commit 79901317ce80 ("n_tty: Don't flush buffer when closing ldis= c"), >>> first merged in kernel release 3.10, caused the following regress= ion >>> in the Gigaset M101 driver: >>> >>> >>> Again, I'll just note my objection to this commit log. >>> >>> This driver was always broken because it never initialized >>> tty->receive_room, >>> but rather relied on common but not guaranteed circumstances to >>> function. >>> >>> The commit noted simply made the underlying bug more evident, but the= >>> root cause was from the original merge commit of this driver. >> >> I must admit I still don't understand that objection. The meaning of t= he >> term "regression" is simply that something which previously worked >> stopped working. It doesn't imply any statement about the root cause. >> >> The ser-gigaset driver worked before the introduction of commit >> 79901317ce80. It didn't work anymore after the introduction of that >> commit. So it is correct, and does not contradict your statements abov= e >> in any way, to state that commit introduced the described regression. >=20 > By asserting that commit 79901317ce80 caused the regression, you're > claiming that this fix is unnecessary for kernel versions prior to 3.10= Correct. > Are you certain that no other sequence of state leads to the same > condition (and thus requiring the same fix) in earlier kernel versions?= Reasonably certain, yes, for three reasons: - There where no reports of that problem before 3.10. - My own tests did never encounter that condition, and even after being made aware of it I was not able to come up with a test that would provoke it with a kernel version before 3.10. - The requirement for line disciplines to set receive_room wasn't (and btw still isn't) documented anywhere, so it's unlikely anything actively relied on it. But if you want to propose that patch for inclusion in earlier stable releases I won't oppose it. --=20 Tilman Schmidt E-Mail: tilman@imap.cc Bonn, Germany Diese Nachricht besteht zu 100% aus wiederverwerteten Bits. Unge=C3=B6ffnet mindestens haltbar bis: (siehe R=C3=BCckseite) --7hQMNKUtdJC8VPm56GwHbkU9DWBnXMOGE Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAEBCAAGBQJV+VHzAAoJEFPuqx0v+F+qyrEH+wWYll84aQHtFU/F1CLqwTQo qm1c9YTVzA0hAPJcKZzlwhw1oSYupBgV2H5JHv9pbgtcrNpLBJ21oMCwhMLaWx2e 0wfvxiZJXUx9xQ85lPvvnmsWLAZ5lTwntYyvyupOsxKS9xERucSi5oLrIzVnJMmD kJjR1M5LntsTNPZS6nYE1q5aOW46Jc1Q9RzmlZJQzAcPdeD4M+ZT4qKes0xUC7J3 MKD9LRBZZ6NoWxGylwko4f2GZkbaqfH24sX13JUMMQz5KcPqx/JHmkDf7+wrbPKN uu9HRTJGOj7qHRQ8Is2yx0RCHitE6jZMqiOLDWAa/caR1sr3DhKDdoKAXEItYTg= =pm2B -----END PGP SIGNATURE----- --7hQMNKUtdJC8VPm56GwHbkU9DWBnXMOGE--