diff options
| author | Chris Bainbridge <chris.bainbridge@gmail.com> | 2015-04-29 21:21:40 +0100 |
|---|---|---|
| committer | Sasha Levin <sasha.levin@oracle.com> | 2015-05-23 15:41:42 -0400 |
| commit | 834706a238191385c41c9368cb231dee75380ae5 (patch) | |
| tree | cf635ce8c5acafb2c8d0ecb13e37dfeb053dce96 /drivers | |
| parent | 51af817611f2c0987030d024f24fc7ea95dd33e6 (diff) | |
ACPI / SBS: Add 5 us delay to fix SBS hangs on MacBook
[ Upstream commit 3349fb64b2927407017d970dd5c4daf3c5ad69f8 ]
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 <chris.bainbridge@gmail.com>
Cc: 3.18+ <stable@vger.kernel.org> # 3.18+
[ rjw: Subject and changelog ]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sasha.levin@oracle.com>
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/acpi/sbshc.c | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/drivers/acpi/sbshc.c b/drivers/acpi/sbshc.c index 26e5b5060523..bf034f8b7c1a 100644 --- a/drivers/acpi/sbshc.c +++ b/drivers/acpi/sbshc.c @@ -14,6 +14,7 @@ #include <linux/delay.h> #include <linux/module.h> #include <linux/interrupt.h> +#include <linux/dmi.h> #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 acpi_smb_hc *hc, u8 protocol, } 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(struct acpi_ec *ec, u8 query_bit, 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; |