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b430acbd7c
acpi_hw_set_mode() double checks its effectiveness by calling acpi_hw_get_mode() -- polling up to 3 seconds. It would be more logical for its caller, acpi_enable() acpi_enable() to do the double-checking. (lets assume that acpi_disable() isn't interesting) The ACPI specification is unclear on this point. Some parts say that the BIOS sets SCI_EN and then returns to the OS, but one part says "OSPM polls the SCI_EN bit until it is sampled SET". The systems I have on hand do the former, SCI_EN is observed to be set upon return from the BIOS. So we move the check up out of acpi_hw_set_mode() up into acpi_enable() where it makes logical sense. Then we replace the 3-second polling loop with a single check. If this check fails, we'll see: "Hardware did not enter ACPI mode" and the system will bail out of ACPI initialization and likely fail to boot. If we see that in practice, we can restore the polling, but put it into acpi_enable. This patch is important if acpi_enable() is used in the resume from S3 path. Many systems today are seen coming back from S3 with SCI_EN off, and then failing to set SCI_EN in response to acpi_enable(). Those systems will take 3 seconds longer to resume due to this loop. However, it is possible that we will not use acpi_enable() in the S3 resume path, and bang SCI_EN directly, which would make the loop harmless, as it would be invisible to all systems except those that need it. Signed-off-by: Len Brown <len.brown@intel.com>
169 lines
5.2 KiB
C
169 lines
5.2 KiB
C
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/******************************************************************************
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*
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* Module Name: hwacpi - ACPI Hardware Initialization/Mode Interface
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*
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*****************************************************************************/
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/*
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* Copyright (C) 2000 - 2010, Intel Corp.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer,
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* without modification.
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* 2. Redistributions in binary form must reproduce at minimum a disclaimer
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* substantially similar to the "NO WARRANTY" disclaimer below
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* ("Disclaimer") and any redistribution must be conditioned upon
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* including a substantially similar Disclaimer requirement for further
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* binary redistribution.
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* 3. Neither the names of the above-listed copyright holders nor the names
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* of any contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* NO WARRANTY
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* HOLDERS OR CONTRIBUTORS BE LIABLE FOR SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
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* STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING
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* IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGES.
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*/
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#include <acpi/acpi.h>
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#include "accommon.h"
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#define _COMPONENT ACPI_HARDWARE
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ACPI_MODULE_NAME("hwacpi")
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/******************************************************************************
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*
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* FUNCTION: acpi_hw_set_mode
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*
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* PARAMETERS: Mode - SYS_MODE_ACPI or SYS_MODE_LEGACY
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*
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* RETURN: Status
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*
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* DESCRIPTION: Transitions the system into the requested mode.
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*
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******************************************************************************/
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acpi_status acpi_hw_set_mode(u32 mode)
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{
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acpi_status status;
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ACPI_FUNCTION_TRACE(hw_set_mode);
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/*
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* ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
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* system does not support mode transition.
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*/
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if (!acpi_gbl_FADT.smi_command) {
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ACPI_ERROR((AE_INFO,
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"No SMI_CMD in FADT, mode transition failed"));
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return_ACPI_STATUS(AE_NO_HARDWARE_RESPONSE);
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}
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/*
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* ACPI 2.0 clarified the meaning of ACPI_ENABLE and ACPI_DISABLE
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* in FADT: If it is zero, enabling or disabling is not supported.
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* As old systems may have used zero for mode transition,
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* we make sure both the numbers are zero to determine these
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* transitions are not supported.
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*/
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if (!acpi_gbl_FADT.acpi_enable && !acpi_gbl_FADT.acpi_disable) {
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ACPI_ERROR((AE_INFO,
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"No ACPI mode transition supported in this system "
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"(enable/disable both zero)"));
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return_ACPI_STATUS(AE_OK);
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}
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switch (mode) {
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case ACPI_SYS_MODE_ACPI:
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/* BIOS should have disabled ALL fixed and GP events */
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status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
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(u32) acpi_gbl_FADT.acpi_enable, 8);
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ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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"Attempting to enable ACPI mode\n"));
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break;
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case ACPI_SYS_MODE_LEGACY:
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/*
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* BIOS should clear all fixed status bits and restore fixed event
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* enable bits to default
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*/
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status = acpi_hw_write_port(acpi_gbl_FADT.smi_command,
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(u32) acpi_gbl_FADT.acpi_disable,
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8);
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ACPI_DEBUG_PRINT((ACPI_DB_INFO,
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"Attempting to enable Legacy (non-ACPI) mode\n"));
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break;
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default:
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return_ACPI_STATUS(AE_BAD_PARAMETER);
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}
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if (ACPI_FAILURE(status)) {
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ACPI_EXCEPTION((AE_INFO, status,
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"Could not write ACPI mode change"));
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return_ACPI_STATUS(status);
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}
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return_ACPI_STATUS(AE_OK);
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}
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/*******************************************************************************
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*
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* FUNCTION: acpi_hw_get_mode
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*
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* PARAMETERS: none
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*
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* RETURN: SYS_MODE_ACPI or SYS_MODE_LEGACY
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*
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* DESCRIPTION: Return current operating state of system. Determined by
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* querying the SCI_EN bit.
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*
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******************************************************************************/
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u32 acpi_hw_get_mode(void)
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{
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acpi_status status;
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u32 value;
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ACPI_FUNCTION_TRACE(hw_get_mode);
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/*
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* ACPI 2.0 clarified that if SMI_CMD in FADT is zero,
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* system does not support mode transition.
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*/
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if (!acpi_gbl_FADT.smi_command) {
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return_UINT32(ACPI_SYS_MODE_ACPI);
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}
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status = acpi_read_bit_register(ACPI_BITREG_SCI_ENABLE, &value);
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if (ACPI_FAILURE(status)) {
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return_UINT32(ACPI_SYS_MODE_LEGACY);
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}
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if (value) {
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return_UINT32(ACPI_SYS_MODE_ACPI);
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} else {
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return_UINT32(ACPI_SYS_MODE_LEGACY);
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}
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}
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