From patchwork Fri Oct 11 10:49:57 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jocelyn Falempe X-Patchwork-Id: 13832405 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 7187FCFD31E for ; Fri, 11 Oct 2024 10:55:46 +0000 (UTC) Received: from gabe.freedesktop.org (localhost [127.0.0.1]) by gabe.freedesktop.org (Postfix) with ESMTP id EB13C10EAB8; Fri, 11 Oct 2024 10:55:45 +0000 (UTC) Authentication-Results: gabe.freedesktop.org; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.b="fcNoYsCV"; dkim-atps=neutral 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 0C39310EAB8 for ; Fri, 11 Oct 2024 10:55:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1728644144; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding; bh=nKrFKiqw6p8t0Q1gg3l5P1jUJ3sq9xk4VDyC3qcm1dY=; b=fcNoYsCVK4eHCpavfxjv6nOcp4MXT6Pkkv67XIgEBPUeh4CedYaY67Fm5kkdk+P51JAzcc hm8x87tIIBHOpnu5zEE+Z998tvxrtX8lbnQcjwpXxparaz4+otZudzz0TOjHSqYgWWOj0w rgT5DvZGseZQz7xDg1Z/4f7zb0OPurw= Received: from mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-103-Izce6minNjm6ZwfdRZ0OGw-1; Fri, 11 Oct 2024 06:55:42 -0400 X-MC-Unique: Izce6minNjm6ZwfdRZ0OGw-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id B450E1954B08; Fri, 11 Oct 2024 10:55:40 +0000 (UTC) Received: from hydra.redhat.com (unknown [10.39.192.224]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 30BED19560AA; Fri, 11 Oct 2024 10:55:35 +0000 (UTC) From: Jocelyn Falempe To: Maarten Lankhorst , Maxime Ripard , Thomas Zimmermann , David Airlie , Daniel Vetter , John Ogness , Javier Martinez Canillas , "Guilherme G . Piccoli" , bluescreen_avenger@verizon.net, Caleb Connolly , dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org Cc: Jocelyn Falempe Subject: [PATCH v4 0/7] drm/log: Introduce a new boot logger to draw the kmsg on the screen Date: Fri, 11 Oct 2024 12:49:57 +0200 Message-ID: <20241011105526.615812-1-jfalempe@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 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: , Errors-To: dri-devel-bounces@lists.freedesktop.org Sender: "dri-devel" drm_log is a simple logger that uses the drm_client API to print the kmsg boot log on the screen. This is not a full replacement to fbcon, as it will only print the kmsg. It will never handle user input, or a terminal because this is better done in userspace. If you're curious on how it looks like, I've put a small demo here: https://people.redhat.com/jfalempe/drm_log/drm_log_draft_boot_v2.mp4 Design decisions: * It uses the drm_client API, so it should work on all drm drivers from the start. * It doesn't scroll the message, that way it doesn't need to redraw the whole screen for each new message. It also means it doesn't have to keep drawn messages in memory, to redraw them when scrolling. * It uses the new non-blocking console API, so it should work well with PREEMPT_RT v2: * Use vmap_local() api, with that change, I've tested it successfully on simpledrm, virtio-gpu, amdgpu, and nouveau. * Stop drawing when the drm_master is taken. This avoid wasting CPU cycle if the buffer is not visible. * Use deferred probe. Only do the probe the first time there is a log to draw. With this, if you boot with quiet, drm_log won't do any modeset. * Add color support for the timestamp prefix, like what dmesg does. * Add build dependency on disabling the fbdev emulation, as they are both drm_client, and there is no way to choose which one gets the focus. v3: * Remove the work thread and circular buffer, and use the new write_thread() console API. * Register a console for each drm driver. v4: * Can be built as a module, even if that's not really useful. * Rebased on top of "drm: Introduce DRM client library" series from Thomas Zimmermann. * Add a Kconfig menu to choose between drm client. * Add suspend/resume callbacks. * Add integer scaling support. Thanks and best regards,