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=-6.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=unavailable 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 DC2E4C1975A for ; Sun, 15 Mar 2020 01:38:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BD59B20637 for ; Sun, 15 Mar 2020 01:38:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726680AbgCOBia (ORCPT ); Sat, 14 Mar 2020 21:38:30 -0400 Received: from cloudserver094114.home.pl ([79.96.170.134]:64875 "EHLO cloudserver094114.home.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726019AbgCOBia (ORCPT ); Sat, 14 Mar 2020 21:38:30 -0400 Received: from 185.80.35.16 (185.80.35.16) (HELO kreacher.localnet) by serwer1319399.home.pl (79.96.170.134) with SMTP (IdeaSmtpServer 0.83.341) id a1b766df2c349fa1; Sat, 14 Mar 2020 10:38:29 +0100 From: "Rafael J. Wysocki" To: Alex Hung Cc: corbet@lwn.net, len.brown@intel.com, pavel@ucw.cz, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, x86@kernel.org, mchehab+samsung@kernel.org, jpoimboe@redhat.com, akpm@linux-foundation.org, pawan.kumar.gupta@linux.intel.com, jgross@suse.com, linux-doc@vger.kernel.org, linux-pm@vger.kernel.org, linux-acpi@vger.kernel.org Subject: Re: [PATCH][RESEND] acpi/x86: add a kernel parameter to disable ACPI BGRT Date: Sat, 14 Mar 2020 10:38:28 +0100 Message-ID: <7409530.ikv4aRezOy@kreacher> In-Reply-To: <20200304225529.6706-1-alex.hung@canonical.com> References: <20200304225529.6706-1-alex.hung@canonical.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Wednesday, March 4, 2020 11:55:29 PM CET Alex Hung wrote: > BGRT is for displaying seamless OEM logo from booting to login screen; > however, this mechanism does not always work well on all configurations > and the OEM logo can be displayed multiple times. This looks worse than > without BGRT enabled. > > This patch adds a kernel parameter to disable BGRT in boot time. This is > easier than re-compiling a kernel with CONFIG_ACPI_BGRT disabled. > > Signed-off-by: Alex Hung > --- > > * Resend to include linux-acpi emailing list > > Documentation/admin-guide/kernel-parameters.txt | 3 +++ > arch/x86/kernel/acpi/boot.c | 10 +++++++++- > 2 files changed, 12 insertions(+), 1 deletion(-) > > diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt > index ffff776..55c5b2f 100644 > --- a/Documentation/admin-guide/kernel-parameters.txt > +++ b/Documentation/admin-guide/kernel-parameters.txt > @@ -442,6 +442,9 @@ > bert_disable [ACPI] > Disable BERT OS support on buggy BIOSes. > > + bgrt_disable [ACPI][X86] > + Disable BGRT to avoid flickering OEM logo. > + > bttv.card= [HW,V4L] bttv (bt848 + bt878 based grabber cards) > bttv.radio= Most important insmod options are available as > kernel args too. > diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c > index 04205ce..d1757ce 100644 > --- a/arch/x86/kernel/acpi/boot.c > +++ b/arch/x86/kernel/acpi/boot.c > @@ -45,6 +45,7 @@ EXPORT_SYMBOL(acpi_disabled); > #define PREFIX "ACPI: " > > int acpi_noirq; /* skip ACPI IRQ initialization */ > +int acpi_nobgrt; /* skip ACPI BGRT */ > int acpi_pci_disabled; /* skip ACPI PCI scan and IRQ initialization */ > EXPORT_SYMBOL(acpi_pci_disabled); > > @@ -1619,7 +1620,7 @@ int __init acpi_boot_init(void) > acpi_process_madt(); > > acpi_table_parse(ACPI_SIG_HPET, acpi_parse_hpet); > - if (IS_ENABLED(CONFIG_ACPI_BGRT)) > + if (IS_ENABLED(CONFIG_ACPI_BGRT) && !acpi_nobgrt) > acpi_table_parse(ACPI_SIG_BGRT, acpi_parse_bgrt); > > if (!acpi_noirq) > @@ -1671,6 +1672,13 @@ static int __init parse_acpi(char *arg) > } > early_param("acpi", parse_acpi); > > +static int __init parse_acpi_bgrt(char *arg) > +{ > + acpi_nobgrt = true; > + return 0; > +} > +early_param("bgrt_disable", parse_acpi_bgrt); > + > /* FIXME: Using pci= for an ACPI parameter is a travesty. */ > static int __init parse_pci(char *arg) > { > Applied as 5.7 material, thanks!