Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2992924AbbEOXPl (ORCPT ); Fri, 15 May 2015 19:15:41 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:43394 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2992881AbbEOXPH (ORCPT ); Fri, 15 May 2015 19:15:07 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Chris Bainbridge , "Rafael J. Wysocki" Subject: [PATCH 4.0 02/60] ACPI / SBS: Add 5 us delay to fix SBS hangs on MacBook Date: Fri, 15 May 2015 16:14:03 -0700 Message-Id: <20150515231018.888981054@linuxfoundation.org> X-Mailer: git-send-email 2.4.0 In-Reply-To: <20150515231018.815421141@linuxfoundation.org> References: <20150515231018.815421141@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2696 Lines: 92 4.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Chris Bainbridge commit 3349fb64b2927407017d970dd5c4daf3c5ad69f8 upstream. Commit 7bc5a2bad0b8 'ACPI: Support _OSI("Darwin") correctly' caused the MacBook firmware to expose the SBS, resulting in intermittent hangs of several minutes on boot, and failure to detect or report the battery. Fix this by adding a 5 us delay to the start of each SMBUS transaction. This timing is the result of experimentation - hangs were observed with 3 us but never with 5 us. Fixes: 7bc5a2bad0b8 'ACPI: Support _OSI("Darwin") correctly' Link: https://bugzilla.kernel.org/show_bug.cgi?id=94651 Signed-off-by: Chris Bainbridge Cc: 3.18+ # 3.18+ [ rjw: Subject and changelog ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Greg Kroah-Hartman --- drivers/acpi/sbshc.c | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) --- a/drivers/acpi/sbshc.c +++ b/drivers/acpi/sbshc.c @@ -14,6 +14,7 @@ #include #include #include +#include #include "sbshc.h" #define PREFIX "ACPI: " @@ -87,6 +88,8 @@ enum acpi_smb_offset { ACPI_SMB_ALARM_DATA = 0x26, /* 2 bytes alarm data */ }; +static bool macbook; + static inline int smb_hc_read(struct acpi_smb_hc *hc, u8 address, u8 *data) { return ec_read(hc->offset + address, data); @@ -132,6 +135,8 @@ static int acpi_smbus_transaction(struct } mutex_lock(&hc->lock); + if (macbook) + udelay(5); if (smb_hc_read(hc, ACPI_SMB_PROTOCOL, &temp)) goto end; if (temp) { @@ -257,12 +262,29 @@ extern int acpi_ec_add_query_handler(str acpi_handle handle, acpi_ec_query_func func, void *data); +static int macbook_dmi_match(const struct dmi_system_id *d) +{ + pr_debug("Detected MacBook, enabling workaround\n"); + macbook = true; + return 0; +} + +static struct dmi_system_id acpi_smbus_dmi_table[] = { + { macbook_dmi_match, "Apple MacBook", { + DMI_MATCH(DMI_BOARD_VENDOR, "Apple"), + DMI_MATCH(DMI_PRODUCT_NAME, "MacBook") }, + }, + { }, +}; + static int acpi_smbus_hc_add(struct acpi_device *device) { int status; unsigned long long val; struct acpi_smb_hc *hc; + dmi_check_system(acpi_smbus_dmi_table); + if (!device) return -EINVAL; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/