linux-stable.git/drivers/acpi/ec.c, branch linux-4.6.y

ACPI-EC: Drop unnecessary check made before calling acpi_ec_delete_query()

2015-11-16T22:29:44+00:00

The acpi_ec_delete_query() function tests whether its argument is NULL
and then returns immediately. Thus the test around the call is not needed.

This issue was detected by using the Coccinelle software.

Signed-off-by: Markus Elfring 
[ rjw: Subject ]
Signed-off-by: Rafael J. Wysocki

ACPI / EC: Fix a race issue in acpi_ec_guard_event()

2015-09-25T23:46:25+00:00

In acpi_ec_guard_event(), EC transaction state machine variables should be
checked with the EC spinlock locked.
The bug doesn't trigger any real issue now because this bug can only occur
when the ec_event_clearing=event mode is applied while there is no user
currently using this mode.

Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki

ACPI / EC: Fix query handler related issues

2015-09-25T23:46:24+00:00

1. acpi_ec_remove_query_handlers()
This patch refines the query handler removal logic implemented in
acpi_ec_remove_query_handler(), making it to invoke new
acpi_ec_remove_query_handlers() API, and ensuring all other removal code
paths to invoke the new API to honor the reference count of the query
handlers.

2. acpi_ec_get_query_handler_by_value()
This patch also refines the query handler search logic originally
implemented in acpi_ec_query(), collecting it into
acpi_ec_get_query_handler_by_value(). And since schedule_work() can ensure
the serilization of acpi_ec_event_handler(), we needn't put the
mutex_lock() around schedule_work().

Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki

ACPI / EC: Fix a memory leak issue in acpi_ec_query()

2015-09-25T23:44:59+00:00

When query handler is not found, "result" is actually stil 0, and
"struct acpi_ec_query" is not NULL, so the deletion code of
"struct acpi_ec_query" at the end of the function cannot be invoked.
As a consequence, memory leak can be observed.

The issue is introduced by this commit:
  Commit: 02b771b64b73226052d6e731a0987db3b47281e9
  Subject: ACPI / EC: Fix an issue caused by the serialized _Qxx

This patch fixes such memory leakage.

Fixes: 02b771b64b73 (ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations)
Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki

Merge branches 'acpi-pci', 'acpi-soc', 'acpi-ec' and 'acpi-osl'

2015-09-01T01:41:19+00:00

* acpi-pci:
  ACPI, PCI: Penalize legacy IRQ used by ACPI SCI

* acpi-soc:
  ACPI / LPSS: Ignore 10ms delay for Braswell

* acpi-ec:
  ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations

* acpi-osl:
  ACPI / osl: replace custom implementation of readq / writeq

ACPI / EC: Fix an issue caused by the serialized _Qxx evaluations

2015-08-25T01:19:32+00:00

It is proven that Windows evaluates _Qxx handlers in a parallel way. This
patch follows this fact, splits _Qxx evaluations from the NOTIFY queue to
form a separate queue, so that _Qxx evaluations can be queued up on
different CPUs rather than being queued up on a CPU0 bound queue.
Event handling related callbacks are also renamed and sorted in this patch.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=94411
Reported-and-tested-by: Gabriele Mazzotta 
Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki

ACPI: Remove FSF mailing addresses

2015-07-08T00:27:32+00:00

There is no need to carry potentially outdated Free Software Foundation
mailing address in file headers since the COPYING file includes it.

Signed-off-by: Jarkko Nikula 
Signed-off-by: Rafael J. Wysocki

ACPI / EC: Fix a code coverity issue when QR_EC transactions are failed.

2015-06-15T12:35:59+00:00

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+  # 3.16+
Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki

ACPI / EC: Fix EC_FLAGS_QUERY_HANDSHAKE platforms using new event clearing timing.

2015-06-15T12:35:59+00:00

It is reported that on several platforms, EC firmware will not respond
non-expected QR_EC (see EC_FLAGS_QUERY_HANDSHAKE, only write QR_EC when
SCI_EVT is set).

Unfortunately, ACPI specification doesn't define when the SCI_EVT should be
cleared by the firmware, thus the original implementation queued up second
QR_EC right after writing QR_EC command and before reading the returned
event value as at that time the SCI_EVT is ensured not cleared. This
behavior is also based on the assumption that the firmware should be able
to return 0x00 to indicate "no outstanding event". This behavior did fix
issues on Samsung platforms where the spurious query value of 0x00 is
supported and didn't break platforms in my test queue.

But recently, specific Acer, Asus, Lenovo platforms keep on blaming this
change.

This patch changes the behavior to re-check the SCI_EVT a bit later and
removes EC_FLAGS_QUERY_HANDSHAKE quirks, hoping this is the Windows
compliant EC driver behavior.

In order to be robust to the possible regressions, instead of removing the
quirk directly, this patch keeps the quirk code, removes the quirk users
and keeps old behavior for Samsung platforms.

Cc: 3.16+  # 3.16+
Link: https://bugzilla.kernel.org/show_bug.cgi?id=94411
Link: https://bugzilla.kernel.org/show_bug.cgi?id=97381
Link: https://bugzilla.kernel.org/show_bug.cgi?id=98111
Reported-and-tested-by: Gabriele Mazzotta 
Reported-and-tested-by: Tigran Gabrielyan 
Reported-and-tested-by: Adrien D 
Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki

ACPI / EC: Add event clearing variation support.

2015-06-15T12:35:59+00:00

We've been suffering from the uncertainty of the SCI_EVT clearing timing.
This patch implements 3 of 4 possible modes to handle SCI_EVT clearing
variations. The old behavior is kept in this patch.

Status: QR_EC is re-checked as early as possible after checking previous
        SCI_EVT. This always leads to 2 QR_EC transactions per SCI_EVT
        indication and the target may implement event queue which returns
        0x00 indicating "no outstanding event".
        This is proven to be a conflict against Windows behavior, but is
        still kept in this patch to make the EC driver robust to the
        possible regressions that may occur on Samsung platforms.
Query: QR_EC is re-checked after the target has handled the QR_EC query
       request command pushed by the host.
Event: QR_EC is re-checked after the target has noticed the query event
       response data pulled by the host.
       This timing is not determined by any IRQs, so we may need to use a
       guard period in this mode, which may explain the existence of the
       ec_guard() code used by the old EC driver where the re-check timing
       is implemented in the similar way as this mode.
Method: QR_EC is re-checked as late as possible after completing the _Qxx
        evaluation. The target may implement SCI_EVT like a level triggered
        interrupt.
        It is proven on kernel bugzilla 94411 that, Windows will have all
        _Qxx evaluations parallelized. Thus unless required by further
        evidences, we needn't implement this mode as it is a conflict of
        the _Qxx parallelism requirement.

Note that, according to the reports, there are platforms that cannot be
handled using the "Status" mode without enabling the
EC_FLAGS_QUERY_HANDSHAKE quirk. But they can be handled with the other
modes according to the tests (kernel bugzilla 97381).

The following log entry can be used to confirm the differences of the 3
modes as it should appear at the different positions for the 3 modes:
  Command(QR_EC) unblocked
Status: appearing after
         EC_SC(W) = 0x84
Query: appearing after
         EC_DATA(R) = 0xXX
       where XX is the event number used to determine _QXX
Event: appearing after first
         EC_SC(R) = 0xX0 SCI_EVT=x BURST=0 CMD=0 IBF=0 OBF=0
       that is next to the following log entry:
         Command(QR_EC) completed by hardware

Link: https://bugzilla.kernel.org/show_bug.cgi?id=94411
Link: https://bugzilla.kernel.org/show_bug.cgi?id=97381
Link: https://bugzilla.kernel.org/show_bug.cgi?id=98111
Reported-and-tested-by: Gabriele Mazzotta 
Reported-and-tested-by: Tigran Gabrielyan 
Reported-and-tested-by: Adrien D 
Signed-off-by: Lv Zheng 
Signed-off-by: Rafael J. Wysocki