From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geert Uytterhoeven Subject: Re: chosen/stdout-path and userland (Re: Can't boot kernel v4.0-rc2 on Koelsch) Date: Wed, 11 Mar 2015 14:23:13 +0100 Message-ID: References: <55003D82.1080601@hurleysoftware.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <55003D82.1080601-WaGBZJeGNqdsbIuE7sb01tBPR1lH4CV8@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Peter Hurley Cc: Laurent Pinchart , Grant Likely , Mark Rutland , Rob Herring , Cao Minh Hiep , Nobuhiro Iwamatsu , Linux-SH , Kuninori Morimoto , Magnus Damm , Simon Horman , Sakato Ryusuke , Yoshihiro Shimoda , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: devicetree@vger.kernel.org Hi Peter, On Wed, Mar 11, 2015 at 2:05 PM, Peter Hurley wrote: > On 03/11/2015 06:08 AM, Geert Uytterhoeven wrote: >> TL;DR >> >> After removing the "console=" parameter from chosen/bootargs, and relying >> solely on chosen/stdout-path, Hiep-san's Linaro userland cannot find the >> console device anymore. > The tty subsystem emits the list of consoles as a space-delimited, single text > line in /sys/class/tty/console/active (alias: /sys/devices/virtual/tty/console/active). Thanks! I didn't know about that virtual file. > The first console listed is the primary console. > tty0 is not resolved to its underlying tty device name. Are you sure about that? Isn't the last one the primary console? root@koelsch:~# cat /sys/class/tty/console/active tty0 ttySC0 If tty0 would be the primary console, getty on /dev/console wouldn't work for my serial console, as only input on the primary console can be read through /dev/console if my memory serves me well (or perhaps this has changed?). Ah, Documentation/ABI/testing/sysfs-tty agrees with me: What: /sys/class/tty/console/active Date: Nov 2010 Contact: Kay Sievers Description: Shows the list of currently configured console devices, like 'tty1 ttyS0'. The last entry in the file is the active device connected to /dev/console. > That said, is the original reporter of this problem even interested in > upgrading their userspace, even if this is fixed in Linaro eventually? > What about other Linaro users? We'll see... > I think the only reasonable course here is to continue to support > "console=" in /chosen/bootargs. Hmm... If you really need it, you can always add it to the U-Boot bootargs variable. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert-Td1EMuHUCqxL1ZNQvxDV9g@public.gmane.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 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html