From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 92852C32750 for ; Fri, 2 Aug 2019 16:02:47 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 660982173E for ; Fri, 2 Aug 2019 16:02:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564761767; bh=Mfej1gsF5s5LDrrvRClXBvNNFTeMEaTN4dRVcQmNCyM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=c6F3zph8rCAPkT89jbUgA60XIcNOYwquUHYNfPSsIZk9VaeG7y1H87MQR0B9KfpKB vm0Y5o8+1zt+PSusddo23VmKBD4PWXvC91hyfOyxpDlY786a5UoaQnsqzSR/2XwDSj HESLxaqoy4rpQw0b+FP93jcEFNivtVF/9u4sLcKM= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388847AbfHBQCq (ORCPT ); Fri, 2 Aug 2019 12:02:46 -0400 Received: from mail.kernel.org ([198.145.29.99]:44116 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388512AbfHBQCq (ORCPT ); Fri, 2 Aug 2019 12:02:46 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 1CBAA216C8; Fri, 2 Aug 2019 16:02:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1564761765; bh=Mfej1gsF5s5LDrrvRClXBvNNFTeMEaTN4dRVcQmNCyM=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=AS7/8i9RSdN8bU4WAPWxwk1bzPeAX3fwadmTZ1GBF3d6XKiiEWtPep5S4095XmhUR JLSqY+mLW1C4fq/z16vInoVfEMgd3UUqT0OR60C706QrlJm1su9felp/0E+WG2jKR/ lXm639h72rLL+0pysOTCQxy7V79+l2Hx0mlkLnxs= Date: Fri, 2 Aug 2019 18:02:43 +0200 From: Greg Kroah-Hartman To: Paul Menzel Cc: linux-serial@vger.kernel.org, Linux Kernel Mailing List , Donald Buczek Subject: Re: Device to write to all (serial) consoles Message-ID: <20190802160243.GA15484@kroah.com> References: <32c2d26f-ec4a-b9a6-b42c-07b27f99ea28@molgen.mpg.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <32c2d26f-ec4a-b9a6-b42c-07b27f99ea28@molgen.mpg.de> User-Agent: Mutt/1.12.1 (2019-06-15) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Aug 02, 2019 at 03:23:08PM +0200, Paul Menzel wrote: > Dear Linux folks, > > > On a lot of devices, like servers, you have more than one serial console, > and you do not always know, how they are numbered. Therefore, we start a > console on ttyS0 and ttyS1. > > In user space, we also would like to write to both consoles to not worry > about the numbering. Writing to `/dev/console` only write to the active > console. So the same data to multiple console devices with just one userspace call? Why? > $ more /proc/consoles # I think > tty0 -WU (EC p ) 4:1 > ttyS0 -W- (E p a) 4:65 > ttyS1 -W- (E p a) 4:65 > > Does a device exist, or can a device be configured so you can write to > all (serial) consoles from user space? With one syscall, not that I know of, sorry. greg k-h