diff options
| author | Lv Zheng <lv.zheng@intel.com> | 2015-06-11 13:21:51 +0800 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2015-06-15 14:35:59 +0200 |
| commit | 66db383439b51b1aa920f3579da644fb5fdb2b7c (patch) | |
| tree | b233971244466cbbd9546b3d48400efb96837a87 /drivers/acpi/ec.c | |
| parent | 3cb02aeb28dd3f1b8a132fa3ecf6db17afd518d6 (diff) | |
ACPI / EC: Fix a code coverity issue when QR_EC transactions are failed.
When the QR_EC transaction fails, the EC_FLAGS_QUERY_PENDING flag prevents
the event handling work queue from being scheduled again.
Though there shouldn't be failed QR_EC transactions, and this gap was
efficiently used for catching and learning the SCI_EVT clearing timing
compliance issues, we need to fix this as we are not fully compatible
with all platforms/Windows to handle SCI_EVT clearing timing correctly.
Fixing this gives the EC driver the chances to recover from a state machine
failure.
So this patch fixes this issue. When nr_pending_queries drops to 0, it
clears EC_FLAGS_QUERY_PENDING at the proper position for different modes in
order to ensure that the SCI_EVT handling can proceed.
In order to be clearer for future ec_event_clearing modes, all checks in
this patch are written in the inclusive style, not the exclusive style.
Cc: 3.16+ <stable@vger.kernel.org> # 3.16+
Signed-off-by: Lv Zheng <lv.zheng@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/acpi/ec.c')
| -rw-r--r-- | drivers/acpi/ec.c | 14 |
1 files changed, 13 insertions, 1 deletions
diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c index 79817ce164c1..9d4761d2f6b7 100644 --- a/drivers/acpi/ec.c +++ b/drivers/acpi/ec.c @@ -512,7 +512,8 @@ static void advance_transaction(struct acpi_ec *ec) */ if (!t || !(t->flags & ACPI_EC_COMMAND_POLL)) { if (ec_event_clearing == ACPI_EC_EVT_TIMING_EVENT && - test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags)) { + (!ec->nr_pending_queries || + test_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags))) { clear_bit(EC_FLAGS_QUERY_GUARDING, &ec->flags); acpi_ec_complete_query(ec); } @@ -1065,6 +1066,17 @@ static void acpi_ec_event_handler(struct work_struct *work) (void)acpi_ec_query(ec, NULL); spin_lock_irqsave(&ec->lock, flags); ec->nr_pending_queries--; + /* + * Before exit, make sure that this work item can be + * scheduled again. There might be QR_EC failures, leaving + * EC_FLAGS_QUERY_PENDING uncleared and preventing this work + * item from being scheduled again. + */ + if (!ec->nr_pending_queries) { + if (ec_event_clearing == ACPI_EC_EVT_TIMING_STATUS || + ec_event_clearing == ACPI_EC_EVT_TIMING_QUERY) + acpi_ec_complete_query(ec); + } } spin_unlock_irqrestore(&ec->lock, flags); |