user/sven/linux.git/drivers/acpi, branch v3.2.67

ACPI / EC: Fix regression due to conflicting firmware behavior between Samsung and Acer.

2015-02-20T00:49:40Z

commit 79149001105f18bd2285ada109f9229ea24a7571 upstream. It is reported that Samsung laptops that need to poll events are broken by the following commit: Commit 3afcf2ece453e1a8c2c6de19cdf06da3772a1b08 Subject: ACPI / EC: Add support to disallow QR_EC to be issued when SCI_EVT isn't set The behaviors of the 2 vendor firmwares are conflict: 1. Acer: OSPM shouldn't issue QR_EC unless SCI_EVT is set, firmware automatically sets SCI_EVT as long as there is event queued up. 2. Samsung: OSPM should issue QR_EC whatever SCI_EVT is set, firmware returns 0 when there is no event queued up. This patch is a quick fix to distinguish the behaviors to make Acer behavior only effective for Acer EC firmware so that the breakages on Samsung EC firmware can be avoided. Fixes: 3afcf2ece453 (ACPI / EC: Add support to disallow QR_EC to be issued ...) Link: https://bugzilla.kernel.org/show_bug.cgi?id=44161 Reported-and-tested-by: Ortwin Glück Signed-off-by: Lv Zheng [ rjw : Subject ] Signed-off-by: Rafael J. Wysocki Signed-off-by: Ben Hutchings Cc: Kamal Mostafa

ACPI / cpuidle: fix deadlock between cpuidle_lock and cpu_hotplug.lock

2014-11-05T20:27:40Z

commit 6726655dfdd2dc60c035c690d9f10cb69d7ea075 upstream. There is a following AB-BA dependency between cpu_hotplug.lock and cpuidle_lock: 1) cpu_hotplug.lock -> cpuidle_lock enable_nonboot_cpus() _cpu_up() cpu_hotplug_begin() LOCK(cpu_hotplug.lock) cpu_notify() ... acpi_processor_hotplug() cpuidle_pause_and_lock() LOCK(cpuidle_lock) 2) cpuidle_lock -> cpu_hotplug.lock acpi_os_execute_deferred() workqueue ... acpi_processor_cst_has_changed() cpuidle_pause_and_lock() LOCK(cpuidle_lock) get_online_cpus() LOCK(cpu_hotplug.lock) Fix this by reversing the order acpi_processor_cst_has_changed() does thigs -- let it first execute the protection against CPU hotplug by calling get_online_cpus() and obtain the cpuidle lock only after that (and perform the symmentric change when allowing CPUs hotplug again and dropping cpuidle lock). Spotted by lockdep. Signed-off-by: Jiri Kosina Signed-off-by: Rafael J. Wysocki Signed-off-by: Ben Hutchings

ACPI / EC: Add support to disallow QR_EC to be issued when SCI_EVT isn't set

2014-09-13T22:41:47Z

commit 3afcf2ece453e1a8c2c6de19cdf06da3772a1b08 upstream. There is a platform refusing to respond QR_EC when SCI_EVT isn't set (Acer Aspire V5-573G). Currently, we rely on the behaviour that the EC firmware can respond something (for example, 0x00 to indicate "no outstanding events") to QR_EC even when SCI_EVT is not set, but the reporter has complained about AC/battery pluging/unpluging and video brightness change delay on that platform. This is because the work item that has issued QR_EC has to wait until timeout in this case, and the _Qxx method evaluation work item queued after QR_EC one is delayed. It sounds reasonable to fix this issue by: 1. Implementing SCI_EVT sanity check before issuing QR_EC in the EC driver's main state machine. 2. Moving QR_EC issuing out of the work queue used by _Qxx evaluation to a seperate IRQ handling thread. This patch fixes this issue using solution 1. By disallowing QR_EC to be issued when SCI_EVT isn't set, we are able to handle such platform in the EC driver's main state machine. This patch enhances the state machine in this way to survive with such malfunctioning EC firmware. Note that this patch can also fix CLEAR_ON_RESUME quirk which also relies on the assumption that the platforms are able to respond even when SCI_EVT isn't set. Fixes: c0d653412fc8 ACPI / EC: Fix race condition in ec_transaction_completed() Link: https://bugzilla.kernel.org/show_bug.cgi?id=82611 Reported-and-tested-by: Alexander Mezin Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki Signed-off-by: Ben Hutchings

ACPI / battery: Retry to get battery information if failed during probing

2014-08-06T17:07:36Z

commit 75646e758a0ecbed5024454507d5be5b9ea9dcbf upstream. Some machines (eg. Lenovo Z480) ECs are not stable during boot up and causes battery driver fails to be loaded due to failure of getting battery information from EC sometimes. After several retries, the operation will work. This patch is to retry to get battery information 5 times if the first try fails. Link: https://bugzilla.kernel.org/show_bug.cgi?id=75581 Reported-and-tested-by: naszar Signed-off-by: Lan Tianyu Signed-off-by: Rafael J. Wysocki [bwh: Backported to 3.2: acpi_battery_update() doesn't take a second parameter] Signed-off-by: Ben Hutchings

ACPI / EC: Fix race condition in ec_transaction_completed()

2014-08-06T17:07:36Z

commit c0d653412fc8450370167a3268b78fc772ff9c87 upstream. There is a race condition in ec_transaction_completed(). When ec_transaction_completed() is called in the GPE handler, it could return true because of (ec->curr == NULL). Then the wake_up() invocation could complete the next command unexpectedly since there is no lock between the 2 invocations. With the previous cleanup, the IBF=0 waiter race need not be handled any more. It's now safe to return a flag from advance_condition() to indicate the requirement of wakeup, the flag is returned from a locked context. The ec_transaction_completed() is now only invoked by the ec_poll() where the ec->curr is ensured to be different from NULL. After cleaning up, the EVT_SCI=1 check should be moved out of the wakeup condition so that an EVT_SCI raised with (ec->curr == NULL) can trigger a QR_SC command. Link: https://bugzilla.kernel.org/show_bug.cgi?id=70891 Link: https://bugzilla.kernel.org/show_bug.cgi?id=63931 Link: https://bugzilla.kernel.org/show_bug.cgi?id=59911 Reported-and-tested-by: Gareth Williams Reported-and-tested-by: Hans de Goede Reported-by: Barton Xu Tested-by: Steffen Weber Tested-by: Arthur Chen Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

ACPI / EC: Remove duplicated ec_wait_ibf0() waiter

2014-08-06T17:07:35Z

commit 9b80f0f73ae1583c22325ede341c74195847618c upstream. After we've added the first command byte write into advance_transaction(), the IBF=0 waiter is duplicated with the command completion waiter implemented in the ec_poll() because: If IBF=1 blocked the first command byte write invoked in the task context ec_poll(), it would be kicked off upon IBF=0 interrupt or timed out and retried again in the task context. Remove this seperate and duplicate IBF=0 waiter. By doing so we can reduce the overall number of times to access the EC_SC(R) status register. Link: https://bugzilla.kernel.org/show_bug.cgi?id=70891 Link: https://bugzilla.kernel.org/show_bug.cgi?id=63931 Link: https://bugzilla.kernel.org/show_bug.cgi?id=59911 Reported-and-tested-by: Gareth Williams Reported-and-tested-by: Hans de Goede Reported-by: Barton Xu Tested-by: Steffen Weber Tested-by: Arthur Chen Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings

ACPI / EC: Add asynchronous command byte write support

2014-08-06T17:07:35Z

commit f92fca0060fc4dc9227342d0072d75df98c1e5a5 upstream. Move the first command byte write into advance_transaction() so that all EC register accesses that can affect the command processing state machine can happen in this asynchronous state machine advancement function. The advance_transaction() function then can be a complete implementation of an asyncrhonous transaction for a single command so that: 1. The first command byte can be written in the interrupt context; 2. The command completion waiter can also be used to wait the first command byte's timeout; 3. In BURST mode, the follow-up command bytes can be written in the interrupt context directly, so that it doesn't need to return to the task context. Returning to the task context reduces the throughput of the BURST mode and in the worst cases where the system workload is very high, this leads to the hardware driven automatic BURST mode exit. In order not to increase memory consumption, convert 'done' into 'flags' to contain multiple indications: 1. ACPI_EC_COMMAND_COMPLETE: converting from original 'done' condition, indicating the completion of the command transaction. 2. ACPI_EC_COMMAND_POLL: indicating the availability of writing the first command byte. A new command can utilize this flag to compete for the right of accessing the underlying hardware. There is a follow-up bug fix that has utilized this new flag. The 2 flags are important because it also reflects a key concept of IO programs' design used in the system softwares. Normally an IO program running in the kernel should first be implemented in the asynchronous way. And the 2 flags are the most common way to implement its synchronous operations on top of the asynchronous operations: 1. POLL: This flag can be used to block until the asynchronous operations can happen. 2. COMPLETE: This flag can be used to block until the asynchronous operations have completed. By constructing code cleanly in this way, many difficult problems can be solved smoothly. Link: https://bugzilla.kernel.org/show_bug.cgi?id=70891 Link: https://bugzilla.kernel.org/show_bug.cgi?id=63931 Link: https://bugzilla.kernel.org/show_bug.cgi?id=59911 Reported-and-tested-by: Gareth Williams Reported-and-tested-by: Hans de Goede Reported-by: Barton Xu Tested-by: Steffen Weber Tested-by: Arthur Chen Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki [bwh: Backported to 3.2: - Adjust context - s/ec->lock/ec->curr_lock/] Signed-off-by: Ben Hutchings

ACPI / EC: Don't count a SCI interrupt as a false one

2014-08-06T17:07:35Z

commit a3cd8d2789c2e265e09377f260e7d2ac9cec81bb upstream. Currently when advance_transaction() is called in EC interrupt handler, if there is nothing driver can do with the interrupt, it will be taken as a false one. But this is not always true, as there may be a SCI EC interrupt fired during normal read/write operation, which should not be counted as a false one. This patch fixes the problem. Signed-off-by: Feng Tang Signed-off-by: Rafael J. Wysocki Signed-off-by: Ben Hutchings

ACPI / EC: Avoid race condition related to advance_transaction()

2014-08-06T17:07:35Z

commit 66b42b78bc1e816f92b662e8888c89195e4199e1 upstream. The advance_transaction() will be invoked from the IRQ context GPE handler and the task context ec_poll(). The handling of this function is locked so that the EC state machine are ensured to be advanced sequentially. But there is a problem. Before invoking advance_transaction(), EC_SC(R) is read. Then for advance_transaction(), there could be race condition around the lock from both contexts. The first one reading the register could fail this race and when it passes the stale register value to the state machine advancement code, the hardware condition is totally different from when the register is read. And the hardware accesses determined from the wrong hardware status can break the EC state machine. And there could be cases that the functionalities of the platform firmware are seriously affected. For example: 1. When 2 EC_DATA(W) writes compete the IBF=0, the 2nd EC_DATA(W) write may be invalid due to IBF=1 after the 1st EC_DATA(W) write. Then the hardware will either refuse to respond a next EC_SC(W) write of the next command or discard the current WR_EC command when it receives a EC_SC(W) write of the next command. 2. When 1 EC_SC(W) write and 1 EC_DATA(W) write compete the IBF=0, the EC_DATA(W) write may be invalid due to IBF=1 after the EC_SC(W) write. The next EC_DATA(R) could never be responded by the hardware. This is the root cause of the reported issue. Fix this issue by moving the EC_SC(R) access into the lock so that we can ensure that the state machine is advanced consistently. Link: https://bugzilla.kernel.org/show_bug.cgi?id=70891 Link: https://bugzilla.kernel.org/show_bug.cgi?id=63931 Link: https://bugzilla.kernel.org/show_bug.cgi?id=59911 Reported-and-tested-by: Gareth Williams Reported-and-tested-by: Hans de Goede Reported-by: Barton Xu Tested-by: Steffen Weber Tested-by: Arthur Chen Signed-off-by: Lv Zheng Signed-off-by: Rafael J. Wysocki [bwh: Backported to 3.2: - Adjust context - Use PREFIX in log message] Signed-off-by: Ben Hutchings

ACPI / EC: Ensure lock is acquired before accessing ec struct members

2014-08-06T17:07:35Z

commit 36b15875a7819a2ec4cb5748ff7096ad7bd86cbb upstream. A bug was introduced by commit b76b51ba0cef ('ACPI / EC: Add more debug info and trivial code cleanup') that erroneously caused the struct member to be accessed before acquiring the required lock. This change fixes it by ensuring the lock acquisition is done first. Found by Aaron Durbin Fixes: b76b51ba0cef ('ACPI / EC: Add more debug info and trivial code cleanup') References: http://crbug.com/319019 Signed-off-by: Puneet Kumar Reviewed-by: Aaron Durbin [olof: Commit message reworded a bit] Signed-off-by: Olof Johansson Signed-off-by: Rafael J. Wysocki [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings