Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751333AbdCZJXC (ORCPT ); Sun, 26 Mar 2017 05:23:02 -0400 Received: from mail-it0-f68.google.com ([209.85.214.68]:35357 "EHLO mail-it0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751142AbdCZJXA (ORCPT ); Sun, 26 Mar 2017 05:23:00 -0400 MIME-Version: 1.0 In-Reply-To: <20170324164202.GI7909@n2100.armlinux.org.uk> References: <20170324162634.8880-1-sjoerd.simons@collabora.co.uk> <20170324164202.GI7909@n2100.armlinux.org.uk> From: Geert Uytterhoeven Date: Sun, 26 Mar 2017 11:22:57 +0200 X-Google-Sender-Auth: n68-DlaRU0EZXbohvCf2zk0YNz4 Message-ID: Subject: Re: [PATCH 0/2] Move uart_register_driver call to device probe for pl010 and sh-sci To: Russell King - ARM Linux Cc: Sjoerd Simons , "linux-serial@vger.kernel.org" , Linux-Renesas , Greg Kroah-Hartman , "linux-kernel@vger.kernel.org" , Jiri Slaby Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1666 Lines: 47 Hi Russell, Sjoerd, On Fri, Mar 24, 2017 at 5:42 PM, Russell King - ARM Linux wrote: > On Fri, Mar 24, 2017 at 05:26:32PM +0100, Sjoerd Simons wrote: >> When testing on a Renesas board with the PL010 serial driver enabled >> serial output broke. Turns out the minor device numbers for both >> drivers happen to overlap, causing whichever driver happened to be the >> second one to register to fail. > > How the **** has the SH serial driver ended up with overlapping device > numbers? Interesting... > What happened to our maintained list of allocated major/minor device > numbers, which is supposed to stop crap like this happening? AMBA PL010 has been assigned major 204, minors 16..31, SCI has been assigned major 204, minors 8..11. Over the years, Renesas SoCs have been gaining more and more serial ports, leading to #define SCI_NPORTS CONFIG_SERIAL_SH_SCI_NR_UARTS with CONFIG_SERIAL_SH_SCI_NR_UARTS=20 in shmobile_defconfig and multi_v7_defconfig (although the maximum value on any supported SoC is 18). But once the value becomes 5 or more, it starts overflowing into the ttyFWx and ttyAMx space. How to solve this? Time for the serial subsystem to switch to dynamic minors, and get rid of the what-is-your-serial-port-called-again-on-this-platform multi-million-euro question? Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds