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authorRonald Tschalär <ronald@innovation.ch>2018-09-30 19:52:51 -0700
committerRafael J. Wysocki <rafael.j.wysocki@intel.com>2018-10-08 08:41:35 +0200
commitca1721c5bee77105829cbd7baab8ee0eab85b06d (patch)
tree7822b0e00f9013f90442bbec0a7b16949fe059ab
parent0238df646e6224016a45505d2c111a24669ebe21 (diff)
downloadlinux-ca1721c5bee77105829cbd7baab8ee0eab85b06d.tar.bz2
ACPI / SBS: Fix GPE storm on recent MacBookPro's
On Apple machines, plugging-in or unplugging the power triggers a GPE for the EC. Since these machines expose an SBS device, this GPE ends up triggering the acpi_sbs_callback(). This in turn tries to get the status of the SBS charger. However, on MBP13,* and MBP14,* machines, performing the smbus-read operation to get the charger's status triggers the EC's GPE again. The result is an endless re-triggering and handling of that GPE, consuming significant CPU resources (> 50% in irq). In the end this is quite similar to commit 3031cddea633 (ACPI / SBS: Don't assume the existence of an SBS charger), except that on the above machines a status of all 1's is returned. And like there, we just want ignore the charger here. Link: https://bugzilla.kernel.org/show_bug.cgi?id=198169 Signed-off-by: Ronald Tschalär <ronald@innovation.ch> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
-rw-r--r--drivers/acpi/sbs.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/drivers/acpi/sbs.c b/drivers/acpi/sbs.c
index 295b59271189..96c5e27967f4 100644
--- a/drivers/acpi/sbs.c
+++ b/drivers/acpi/sbs.c
@@ -441,9 +441,13 @@ static int acpi_ac_get_present(struct acpi_sbs *sbs)
/*
* The spec requires that bit 4 always be 1. If it's not set, assume
- * that the implementation doesn't support an SBS charger
+ * that the implementation doesn't support an SBS charger.
+ *
+ * And on some MacBooks a status of 0xffff is always returned, no
+ * matter whether the charger is plugged in or not, which is also
+ * wrong, so ignore the SBS charger for those too.
*/
- if (!((status >> 4) & 0x1))
+ if (!((status >> 4) & 0x1) || status == 0xffff)
return -ENODEV;
sbs->charger_present = (status >> 15) & 0x1;