From patchwork Fri Sep 15 08:28:20 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jocelyn Falempe X-Patchwork-Id: 13386551 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from gabe.freedesktop.org (gabe.freedesktop.org [131.252.210.177]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id B97E2EE6447 for ; Fri, 15 Sep 2023 08:35:43 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id A101510E5CD; Fri, 15 Sep 2023 08:35:42 +0000 (UTC) Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by gabe.freedesktop.org (Postfix) with ESMTPS id 1FC8E10E5CC for ; Fri, 15 Sep 2023 08:35:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1694766939; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding; bh=3z6Vo+ImVC82WYLqo4WzC78sdixCQlRqUPDN2j6e6vY=; b=JOTxEduiqyobVwzY6kr3LYsfBj4XZ2BOqr181vHW7atekjn2UuIeGy/oeeDfvgMBgJjvmz 09wmKxsrRUPcjJoxrNxnAE5bkOXDiRxwO9sxA3B9mL9cJkCOMUwCFo4euxGkFMyL45TBm6 /ufN4JjauvvO76p5n1azsEwNIpR8KaQ= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-59-EJnJsGoGPlG16mWzTo9JEw-1; Fri, 15 Sep 2023 04:35:35 -0400 X-MC-Unique: EJnJsGoGPlG16mWzTo9JEw-1 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.rdu2.redhat.com [10.11.54.1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 858E5800888; Fri, 15 Sep 2023 08:35:34 +0000 (UTC) Received: from hydra.redhat.com (unknown [10.39.194.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id CAA2640C2070; Fri, 15 Sep 2023 08:35:27 +0000 (UTC) From: Jocelyn Falempe To: dri-devel@lists.freedesktop.org, tzimmermann@suse.de, airlied@redhat.com, maarten.lankhorst@linux.intel.com, mripard@kernel.org, daniel@ffwll.ch, javierm@redhat.com, bluescreen_avenger@verizon.net Subject: [RFC][PATCH v2 0/2] drm/panic: Add a drm panic handler Date: Fri, 15 Sep 2023 10:28:20 +0200 Message-ID: <20230915083307.1185571-1-jfalempe@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com X-BeenThere: dri-devel@lists.freedesktop.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Direct Rendering Infrastructure - Development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Jocelyn Falempe Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" This introduces a new drm panic handler, which displays a message when a panic occurs. So when fbcon is disabled, you can still see a kernel panic. This is one of the missing feature, when disabling VT/fbcon in the kernel: https://www.reddit.com/r/linux/comments/10eccv9/config_vtn_in_2023/ Fbcon can be replaced by a userspace kms console, but the panic screen must be done in the kernel. This is a proof of concept, and works only with simpledrm, using a new get_scanout_buffer() api To test it, make sure you're using the simpledrm driver, and trigger a panic: echo c > /proc/sysrq-trigger v2 * Use get_scanout_buffer() instead of the drm client API. (Thomas Zimmermann) * Add the panic reason to the panic message (Nerdopolis) * Add an exclamation mark (Nerdopolis) I didn't reuse the fbdev functions yet, that would need some fbdev refactoring, because they rely on struct fb_info, and struct vc_data (for font/console). But I still plan to at least try it for v3. A few more though: 1) what about gpu with multiple monitor connected ? maybe get_scanout_buffer() could return a list of scanout buffers ? 2) I think for some GPU drivers, there might need a flush_scanout_buffer() function, that should be called after the scanout buffer has been filled ? Best regards, Jocelyn Falempe (2): drm/panic: Add a drm panic handler drm/simpledrm: Add drm_panic support drivers/gpu/drm/Kconfig | 11 ++ drivers/gpu/drm/Makefile | 1 + drivers/gpu/drm/drm_drv.c | 3 + drivers/gpu/drm/drm_panic.c | 270 +++++++++++++++++++++++++++++++ drivers/gpu/drm/tiny/simpledrm.c | 17 ++ include/drm/drm_drv.h | 14 ++ include/drm/drm_panic.h | 41 +++++ 7 files changed, 357 insertions(+) create mode 100644 drivers/gpu/drm/drm_panic.c create mode 100644 include/drm/drm_panic.h base-commit: 2dde18cd1d8fac735875f2e4987f11817cc0bc2c