Return-Path: Date: Tue, 23 Aug 2016 01:57:59 +0200 From: Sebastian Reichel To: One Thousand Gnomes Cc: Pavel Machek , Marcel Holtmann , Rob Herring , Arnd Bergmann , Greg Kroah-Hartman , Jiri Slaby , Peter Hurley , NeilBrown , "Dr . H . Nikolaus Schaller" , Linus Walleij , "open list:BLUETOOTH DRIVERS" , "linux-serial@vger.kernel.org" , "linux-kernel@vger.kernel.org" Subject: Re: [RFC PATCH 0/3] UART slave device bus Message-ID: <20160822235758.gh33xupgyroye5wa@earth> References: <2775954.hrE2UdODgU@wuerfel> <20160822180254.5c95af7c@lxorguk.ukuu.org.uk> <20160822183849.6dfdb9d2@lxorguk.ukuu.org.uk> <2D07EA08-1055-4292-96B3-32913EC9BBE1@holtmann.org> <20160822223223.398ee72d@lxorguk.ukuu.org.uk> <20160822220017.GA10689@amd> <20160822235414.4b2f8712@lxorguk.ukuu.org.uk> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="z2xuyqkzrqtqmspz" In-Reply-To: <20160822235414.4b2f8712@lxorguk.ukuu.org.uk> List-ID: --z2xuyqkzrqtqmspz Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable Hi, On Mon, Aug 22, 2016 at 11:54:14PM +0100, One Thousand Gnomes wrote: > On Tue, 23 Aug 2016 00:00:17 +0200 > Pavel Machek wrote: >=20 > > On Mon 2016-08-22 22:32:23, One Thousand Gnomes wrote: > > > > why would we even have it create a /dev/ttyX for these devices in t= he first place. Lets just not create an uevent for it and lets not create a= dev_t for it. =20 > > >=20 > > > Because if you don't it's a regression. It's not permissible to break > > > existing userspace. =20 > >=20 > > Well... it would be good to do the right thing, at least in the places > > where we can. > >=20 > > Yes, renumbering people's serials is bad, OTOH for new platforms it > > would be nice not to expose ttyS15 which can only return -EBUSY. >=20 > That would still be a regression. Not everyone even uses the kernel > bluetooth stack. It would only return EBUSY if you had done an "up" > on it via the direct bluetooth stack. So it returns EBUSY when uart-bus is used. Since uart-bus is about hardwired devices that's basically always. Also I wonder how relevant your "I want to handle all UART stuff out of kernel" scenario is for uart-bus, which is about in-kernel UART drivers. -- Sebastian --z2xuyqkzrqtqmspz Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 iQIcBAEBCgAGBQJXu5GEAAoJENju1/PIO/qavLAP/RhkbuywO8MbocXB5/wxiqsj XvU55UKS9O8yNpQAOHKo9gO0FRtYElIwGG34uYt3aiJwKdqblG7B/ErWKYu64ubg Vz29/CmStRIJEfSaxK86uavhWkWXNMxWqZz4TzBSEGXb6QG44UAEQV5GeQkdtich urUjZjSWj8YPz0EoGJOve7Y+dB3tij2FtSIauJ2mMbSt/Nds5uQ/ZiWVUw58WgkA XQc3PlmAV/mEdJdKq3kyObGU9xciKGjyYZd0bO/YwukmyApX0mdb4Bf4VgpSALaj HDGWN8ANMDK62sW6hdN5UJOGV+JZM21Pg3PfaSJPKVxvrUPQEO2ZBhcjg29Lfs3u l32zbp/RlGslPV0bTuus9FoC1W2VkjqpScXL/0uOumYDgInGw1DFqfxDIUn3AMnA OnScFoV98TClGYUxx8xCRjqe2VtXTSjVilOzIJoj4rEURHssCTDkbvo3bMeGVhLg 6bvkAcW72Yh3bkKkkcI3ScCo0LHmdhv/NsQO6ILfDA8kXlDOoCOn2HP+CDug5ghu JH5MXpR4kexRrIkndtNmVVsTc9hjkDCt/+y0T1RyvpArQtZYsYRrsIWxee79HBGU 4tYF/QoG/oEmWF4LNIKxSCmArdhXDUQJK9j8XyOQgPY/vGdFzgeCM8x+FflXN7mM K8iPRbu9CG/mlO7kln42 =oosx -----END PGP SIGNATURE----- --z2xuyqkzrqtqmspz--