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 X-Spam-Level: X-Spam-Status: No, score=-2.0 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 49CB6C04E30 for ; Mon, 9 Dec 2019 19:12:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 15A05206D3 for ; Mon, 9 Dec 2019 19:12:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="mOBkGJs+" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726879AbfLITMq (ORCPT ); Mon, 9 Dec 2019 14:12:46 -0500 Received: from mail-qk1-f196.google.com ([209.85.222.196]:34291 "EHLO mail-qk1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726230AbfLITMq (ORCPT ); Mon, 9 Dec 2019 14:12:46 -0500 Received: by mail-qk1-f196.google.com with SMTP id d202so14129036qkb.1; Mon, 09 Dec 2019 11:12:45 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:from:date:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=q2n3Ep3oTE0Cvd+RIe5uHUhooskIBzQpsbGGxGO3Chk=; b=mOBkGJs+38FH69k+F7+s119d8qSe86/v7VrixRpQhmiBBj7z/n2jAeIMjE0pnagRjY 6R9W1S5UYd7sagDHr9/SW2+SN+rNkp63Dg9qTPP0dAg3LNHbEYbUHgB7IQbjWYjXyIyn Bi7zbwed108OaMBZ+QJRZJp9ialxwYt7gwbeV31gnABXV6FRu85ASppn0ecWefBt+cxg WOQ5G30lzC1duAlaipqaecjxBgGl9ogRnHkdlCzoWANSJk0SIC1CcfVApvVWlb61fJBa bcYQPp02ZTPo9skJMoxd3hDbLc6iCml/jMOeeegDk75vuaUX5qu0TMmIl+VpFzwdfW7B 2WKA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:from:date:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to:user-agent; bh=q2n3Ep3oTE0Cvd+RIe5uHUhooskIBzQpsbGGxGO3Chk=; b=dPoK+S0oRJhShRBsgDI4Ce+QiaRxmDz+klp+gbsaFo5kiJXNCNf1XF/Ukgc0FVMW6a JCec29x752Qy40UGFyv7YxWWR5Ks7Ci3FcGq7+ChMoKUQc+YwzWuUXOOfMzRCypwfBwD QYwBpOwwjQ/VWFkVkCgp76iEJFURFnDwV73tIpLeCOAfqyoNKjchanC7xaytWMNg6eXO I+I0N/lYqTiTVensZeL5mv+wq4rbajaOx/FQNa3+WZ+xfgGSBwFzPIQ2gSqjhdxvfXpY uye55ZZX6sOjjqJfEdHLgx+Q8I93QfhyTh0mys7NxRygD3bOm9FVxw9JmPwIrdOYjdeH qQnA== X-Gm-Message-State: APjAAAUTfiAZaUJasWtrwPYnaVH7Qgl/5V0ZhEIlseWcm7bN4s/z+J+G 0Sq3OJ7U4j2WavCxSxZxh/k= X-Google-Smtp-Source: APXvYqzieak4udGQsL5U1LHgU7o/hQRs0IaSDXl7JFWCmqe0v+TRHhSL6p4TUPtXh5v3iZSdTs/k2A== X-Received: by 2002:a37:5b41:: with SMTP id p62mr4897197qkb.442.1575918764987; Mon, 09 Dec 2019 11:12:44 -0800 (PST) Received: from rani.riverdale.lan ([2001:470:1f07:5f3::b55f]) by smtp.gmail.com with ESMTPSA id y26sm176564qtc.94.2019.12.09.11.12.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 09 Dec 2019 11:12:44 -0800 (PST) From: Arvind Sankar X-Google-Original-From: Arvind Sankar Date: Mon, 9 Dec 2019 14:12:42 -0500 To: Ard Biesheuvel Cc: linux-efi@vger.kernel.org, Ingo Molnar , Thomas Gleixner , linux-kernel@vger.kernel.org, Andy Shevchenko , Arvind Sankar , Bhupesh Sharma , Masayoshi Mizuma Subject: Re: [PATCH 6/6] efi/earlycon: Remap entire framebuffer after page initialization Message-ID: <20191209191242.GA3075464@rani.riverdale.lan> References: <20191206165542.31469-1-ardb@kernel.org> <20191206165542.31469-7-ardb@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20191206165542.31469-7-ardb@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Dec 06, 2019 at 04:55:42PM +0000, Ard Biesheuvel wrote: > From: Andy Shevchenko > > When commit 69c1f396f25b > > "efi/x86: Convert x86 EFI earlyprintk into generic earlycon implementation" > > moved the x86 specific EFI earlyprintk implementation to a shared location, > it also tweaked the behaviour. In particular, it dropped a trick with full > framebuffer remapping after page initialization, leading to two regressions: > 1) very slow scrolling after page initialization, > 2) kernel hang when the 'keep_bootcon' command line argument is passed. > > Putting the tweak back fixes #2 and mitigates #1, i.e., it limits the slow > behavior to the early boot stages, presumably due to eliminating heavy > map()/unmap() operations per each pixel line on the screen. > Could the efi earlycon have an interaction with PCI resource allocation, similar to what commit dcf8f5ce3165 ("drivers/fbdev/efifb: Allow BAR to be moved instead of claiming it") fixed for efifb?