From patchwork Mon Aug 17 13:27:25 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrzej Pietrasiewicz X-Patchwork-Id: 11718251 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id A41DA138C for ; Mon, 17 Aug 2020 13:27:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8A7E32072D for ; Mon, 17 Aug 2020 13:27:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728503AbgHQN1g (ORCPT ); Mon, 17 Aug 2020 09:27:36 -0400 Received: from bhuna.collabora.co.uk ([46.235.227.227]:44376 "EHLO bhuna.collabora.co.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728465AbgHQN1g (ORCPT ); Mon, 17 Aug 2020 09:27:36 -0400 Received: from [127.0.0.1] (localhost [127.0.0.1]) (Authenticated sender: andrzej.p) with ESMTPSA id 9DF82297B9C From: Andrzej Pietrasiewicz To: linux-kernel@vger.kernel.org Cc: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , Greg Kroah-Hartman , Jiri Slaby , Dmitry Torokhov , Andrzej Pietrasiewicz , linux-input@vger.kernel.org, dri-devel@lists.freedesktop.org, kernel@collabora.com Subject: [PATCH v2 0/2] Add configurable handler to execute a compound action Date: Mon, 17 Aug 2020 15:27:25 +0200 Message-Id: <20200817132727.14564-1-andrzej.p@collabora.com> X-Mailer: git-send-email 2.17.1 Sender: linux-input-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-input@vger.kernel.org This is a follow-up of this thread: https://www.spinics.net/lists/linux-input/msg68446.html It only touches DRM (dri-devel) in such a way that it changes the help message of sysrq_drm_fb_helper_restore_op, otherwise it is unrelated to DRM. Patch 2/2 adds a configurable handler to execute a compound action. Userland might want to execute e.g. 'w' (show blocked tasks), followed by 's' (sync), followed by 1000 ms delay and then followed by 'c' (crash) upon a single magic SysRq. Or one might want to execute the famous "Raising Elephants Is So Utterly Boring" action. This patch adds a configurable handler, triggered with 'C', for this exact purpose. The user specifies the composition of the compound action using syntax similar to getopt, where each letter corresponds to an individual action and a colon followed by a number corresponds to a delay of that many milliseconds, e.g.: ws:1000c or r:100eis:1000ub An example of userspace that wants to perform a compound action is Chrome OS, where SysRq-X (pressed for the second time within a certain time period from the first time) causes showing the locked tasks, syncing, waiting a 1000 ms delay and crashing the system. Since all the slots in the sysrq_key_table[] are already taken or reserved, patch 1/2 extends it to cover also capital letter versions. v1..v2: - used toupper() instead of opencoding it (Jiri Slaby) - updated help message of sysrq_drm_fb_helper_restore_op (Jiri Slaby) - used unsigned int for specifying delays (Jiri Slaby) - improved printed messages formatting (Jiri Slaby) Andrzej Pietrasiewicz (2): tty/sysrq: Extend the sysrq_key_table to cover capital letters tty/sysrq: Add configurable handler to execute a compound action Documentation/admin-guide/sysrq.rst | 11 +++ drivers/gpu/drm/drm_fb_helper.c | 2 +- drivers/tty/sysrq.c | 129 +++++++++++++++++++++++++++- include/linux/sysrq.h | 1 + 4 files changed, 140 insertions(+), 3 deletions(-) base-commit: 9123e3a74ec7b934a4a099e98af6a61c2f80bbf5