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 3F952C433EF for ; Wed, 19 Jan 2022 11:48:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240881AbiASLsF (ORCPT ); Wed, 19 Jan 2022 06:48:05 -0500 Received: from mail-ua1-f46.google.com ([209.85.222.46]:42929 "EHLO mail-ua1-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233640AbiASLsE (ORCPT ); Wed, 19 Jan 2022 06:48:04 -0500 Received: by mail-ua1-f46.google.com with SMTP id p1so3923119uap.9; Wed, 19 Jan 2022 03:48:04 -0800 (PST) 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=JCbX2OMJvl/EE6vcwTdZbTk0S6N5nx5++Qk7hJWCnWw=; b=6ynxB6zjuNh7C8y/KfaG2P69DmrTo2wKsYLHt92OpNUH/BFq9jbiF9j+J/pYtv6Txw TE11ImT4QTVH84vkcclXRWugm3LAhfGthsQm18atYI7YIdQLQ3ayUB243zVYDxoDdIuq 5PoQGep5MHgalvtPD27G85pEVaCGm/t7CO+H1M5TDayjOmXzXntQQTxKrMbdjIWqeaqi mE7qBQovTIrYoVsTNk1aldqap6eH7B/5Zp0RGO5wm58TuU1qnaeitQX5q+chN7y95dr4 clFOC0A/JIS3kyFfAoO7FWNUL7BTOtBDZCd+3i7ANJa9wjslu4ZjI/gUz+PE2iPARNXg JXvg== X-Gm-Message-State: AOAM531QajfPvZ+agOBlv3uoumIS9F2cBUB7mt+FYi+wGnMb5s5BMtjR 2jb8EbaP6m1MzAdCTENYSRfBI4C/jmWJlQ== X-Google-Smtp-Source: ABdhPJxTkH8KHcNKagOL1iqb4sxFVVyIV2kicNzKsbcUqtJjKDX4xWk2WC0LpPLFEXQsoMwUCXRFPA== X-Received: by 2002:a05:6102:b02:: with SMTP id b2mr10568744vst.52.1642592883776; Wed, 19 Jan 2022 03:48:03 -0800 (PST) Received: from mail-ua1-f54.google.com (mail-ua1-f54.google.com. [209.85.222.54]) by smtp.gmail.com with ESMTPSA id b8sm4426601vsl.19.2022.01.19.03.48.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 19 Jan 2022 03:48:02 -0800 (PST) Received: by mail-ua1-f54.google.com with SMTP id l1so2101791uap.8; Wed, 19 Jan 2022 03:48:02 -0800 (PST) X-Received: by 2002:a05:6102:3581:: with SMTP id h1mr11427171vsu.5.1642592881909; Wed, 19 Jan 2022 03:48:01 -0800 (PST) MIME-Version: 1.0 References: <20220119110839.33187-1-deller@gmx.de> <20220119110839.33187-3-deller@gmx.de> In-Reply-To: From: Geert Uytterhoeven Date: Wed, 19 Jan 2022 12:47:50 +0100 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH 2/2] Revert "fbcon: Disable accelerated scrolling" To: Greg Kroah-Hartman Cc: Helge Deller , Thomas Zimmermann , Linux Fbdev development list , Sven Schnelle , Linus Torvalds , Javier Martinez Canillas , Daniel Vetter , Ilia Mirkin , Tomi Valkeinen , DRI Development , Jani Nikula , Pavel Machek , Linux Kernel Mailing List , Gerd Hoffmann , Sam Ravnborg , Claudio Suarez Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org Hi Greg, On Wed, Jan 19, 2022 at 12:28 PM Greg Kroah-Hartman wrote: > On Wed, Jan 19, 2022 at 12:22:55PM +0100, Greg Kroah-Hartman wrote: > > On Wed, Jan 19, 2022 at 12:08:39PM +0100, Helge Deller wrote: > > > This reverts commit 39aead8373b3c20bb5965c024dfb51a94e526151. > > > > > > Revert this patch. This patch started to introduce the regression that > > > all hardware acceleration of more than 35 existing fbdev drivers were > > > bypassed and thus fbcon console output for those was dramatically slowed > > > down by factor of 10 and more. > > > > > > Reverting this commit has no impact on DRM, since none of the DRM drivers are > > > tagged with the acceleration flags FBINFO_HWACCEL_COPYAREA, > > > FBINFO_HWACCEL_FILLRECT or others. > > > > > > Signed-off-by: Helge Deller > > As for "why", I think there was a number of private bugs that were > > reported in this code, which is why it was removed. I do not think it > > can be safely added back in without addressing them first. Let me go > > dig through my email to see if I can find them... > > Ah, no, that was just the soft scrollback code I was thinking of, which So the bugs argument is moot. > was a different revert and is still gone, thankfully :) FTR, not everyone else was thankful about that one... > This one was just removed because Daniel noticed that only 3 drivers > used this (nouveau, omapdrm, and gma600), so this shouldn't have caused > any regressions in any other drivers like you are reporting here. > > So perhaps this regression is caused by something else? 1. Daniel's patch was not CCed to linux-fbdev, 2. When I discovered the patch, I pointed out that the premise of 3 drivers was not true, and that it affects 32 more fbdev drivers[1] . The patch was applied regardless. 3. When the patch was suggested for backporting, I pointed out the same[2]. The patch was backported regardless. [1] https://lore.kernel.org/r/alpine.DEB.2.22.394.2010311116530.379363@ramsan.of.borg/ [2] https://lore.kernel.org/r/CAMuHMdXRgam2zahPEGcw8+76Xm-0AO-Ci9-YmVa5JpTKVHphRw@mail.gmail.com/ Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds