Commit 1ffb8d03 authored by Alex Hung's avatar Alex Hung Committed by Rafael J. Wysocki
Browse files

acpi/x86: add a kernel parameter to disable ACPI BGRT 



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: default avatarAlex Hung <alex.hung@canonical.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent fa0fca68

Documentation/admin-guide/kernel-parameters.txt

+3 −0
Original line number Diff line number Diff line
@@ -450,6 +450,9 @@ 
	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.

arch/x86/kernel/acpi/boot.c

+9 −1
Original line number Diff line number Diff line
@@ -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)

{

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