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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 07CA9C433FE for ; Mon, 17 Jan 2022 16:38:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241103AbiAQQij (ORCPT ); Mon, 17 Jan 2022 11:38:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39968 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235274AbiAQQih (ORCPT ); Mon, 17 Jan 2022 11:38:37 -0500 Received: from mail-oi1-x229.google.com (mail-oi1-x229.google.com [IPv6:2607:f8b0:4864:20::229]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 39D5EC061574 for ; Mon, 17 Jan 2022 08:38:37 -0800 (PST) Received: by mail-oi1-x229.google.com with SMTP id y14so24244083oia.9 for ; Mon, 17 Jan 2022 08:38:37 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ffwll.ch; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=TI+T6c0N7K3peD5+tx0Z05C/5JTL5JQSb7+Gvq9P/90=; b=HQGZtxqrdYuyGFZCoIvTbvoyDbXOEqvEXtal37kXs0fwaT8d5+UBqIyUt03jdv+LWO YTghMijy/JpjTAiDS1lH/dgiOJTG8ZqcJ/YNZ+hCWHG9ArTln0xRRiNFQnToVrr3UKbu cFRDl3Edik/s2Uzs5ZHZggDK4AJW0zTqhLH+U= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=TI+T6c0N7K3peD5+tx0Z05C/5JTL5JQSb7+Gvq9P/90=; b=B2L+mtp83swNVQH9MAjA9t2eVKrbbSsLLtY7OBMyxE5MagB8mM3rhOb3w1wELY5ppA gBfByS/kCAjtTaws3N0DAszJgXXQ4xkPoTYPIfacLM1jPpzwm/Vf58DRQtOe7QwbMZ// nRhBy8F5EwjD3jIfGlqg8kjA6RiQ6ZHeCLx1mXtRiYyKMvngenRwBc6bbRueoZhf78w9 XV1JYcoKuHXmNgzB4n1touKmIybx95nBtbpzxUEzAbwnZQcckmWea4EnNqx/QZiIZvPB bEsHVltZ+18pLf87Ekmm86dXZwNpQGSncaMT3CCPyzQ6m04GWUq2zfpwurqQ3Dle81f4 Bmvw== X-Gm-Message-State: AOAM532Dw80h2AGvXrdurcn7rG7WG68LRPOW3UGh9rXJrmCSwd++rBBm Yibqt8HUPNQUar1G1xT59Qshg8vEqc7zvP4ROI8RMA== X-Google-Smtp-Source: ABdhPJwtZw3vr6mz2n3FOqglwVtWUYAgk2YKpHpdVERnXV0uo5vcLRo2/BjpnL+iKV8aeXnIyLfjH1gWrAF+/H/EIvA= X-Received: by 2002:a05:6808:3a3:: with SMTP id n3mr9217462oie.128.1642437516512; Mon, 17 Jan 2022 08:38:36 -0800 (PST) MIME-Version: 1.0 References: <97d49bca-f5f7-dba4-b62d-b6fcdd4276ac@suse.de> In-Reply-To: From: Daniel Vetter Date: Mon, 17 Jan 2022 17:38:25 +0100 Message-ID: Subject: Re: [PATCH] MAINTAINERS: Add Helge as fbdev maintainer To: Helge Deller Cc: Thomas Zimmermann , Linus Torvalds , "airlied@gmail.com" , linux-fbdev@vger.kernel.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Javier Martinez Canillas , Geert Uytterhoeven Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Jan 17, 2022 at 5:22 PM Helge Deller wrote: > > On 1/17/22 16:58, Thomas Zimmermann wrote: > > Hi > > > > Am 17.01.22 um 16:42 schrieb Helge Deller: > >> [...] > >>>> c) reintroduce the state where fbcon is fast on fbdev. This is important for non-DRM machines, > >>>> either when run on native hardware or in an emulator. > >>>> d) not break DRM development > >>>> > >>>> Especially regarding c) I complained in [1] and got no feedback. I really would like to > >>>> understand where the actual problems were and what's necessary to fix them. > >>>> > >>>> Helge > >>>> > >>>> [1] https://lore.kernel.org/r/feea8303-2b83-fc36-972c-4fc8ad723bde@gmx.de > > > > Seems like few people read linux-fbdev these days. > > I suggest to partly revert the patch to the point were performance > > gets better again. > Yes, *please*! > That would solve my biggest concern. > > As far as I can see that's only 2 commits to be reverted: > b3ec8cdf457e - "fbdev: Garbage collect fbdev scrolling acceleration, part 1 (from TODO list)" > 39aead8373b3 - "fbcon: Disable accelerated scrolling"for-next-next > > I think both were not related to any 0-day bug reports (but again, I might be wrong). syzbot, not 0day, and there's like a sea of them unfortunately. There's all kinds of funny races going on when resizing consoles (due to bad locking design) which then blow up, especially in less tested code. For the sw rendering we've merged a bunch of patches, but you pretty much have to assume that it's all fairly broken code until it's rewritten and fully covered with tests. Shadowfb + memcpy is probably much faster for restoring scrolling performance than anything else really. -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch