176 lines
6.6 KiB
Diff
176 lines
6.6 KiB
Diff
Bugzilla: 1003602
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Upstream-status: Queued for 3.15 https://git.kernel.org/cgit/linux/kernel/git/rafael/linux-pm.git/commit/?id=27095111cbafd3212c7e9a4a8cef1099b7520ca8
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From 27095111cbafd3212c7e9a4a8cef1099b7520ca8 Mon Sep 17 00:00:00 2001
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From: Kieran Clancy <clancy.kieran@gmail.com>
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Date: Fri, 28 Feb 2014 14:12:28 +0000
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Subject: ACPI / EC: Clear stale EC events on Samsung systems
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A number of Samsung notebooks (530Uxx/535Uxx/540Uxx/550Pxx/900Xxx/etc)
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continue to log events during sleep (lid open/close, AC plug/unplug,
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battery level change), which accumulate in the EC until a buffer fills.
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After the buffer is full (tests suggest it holds 8 events), GPEs stop
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being triggered for new events. This state persists on wake or even on
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power cycle, and prevents new events from being registered until the EC
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is manually polled.
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This is the root cause of a number of bugs, including AC not being
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detected properly, lid close not triggering suspend, and low ambient
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light not triggering the keyboard backlight. The bug also seemed to be
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responsible for performance issues on at least one user's machine.
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Juan Manuel Cabo found the cause of bug and the workaround of polling
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the EC manually on wake.
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The loop which clears the stale events is based on an earlier patch by
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Lan Tianyu (see referenced attachment).
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This patch:
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- Adds a function acpi_ec_clear() which polls the EC for stale _Q
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events at most ACPI_EC_CLEAR_MAX (currently 100) times. A warning is
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logged if this limit is reached.
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- Adds a flag EC_FLAGS_CLEAR_ON_RESUME which is set to 1 if the DMI
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system vendor is Samsung. This check could be replaced by several
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more specific DMI vendor/product pairs, but it's likely that the bug
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affects more Samsung products than just the five series mentioned
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above. Further, it should not be harmful to run acpi_ec_clear() on
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systems without the bug; it will return immediately after finding no
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data waiting.
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- Runs acpi_ec_clear() on initialisation (boot), from acpi_ec_add()
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- Runs acpi_ec_clear() on wake, from acpi_ec_unblock_transactions()
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References: https://bugzilla.kernel.org/show_bug.cgi?id=44161
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References: https://bugzilla.kernel.org/show_bug.cgi?id=45461
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References: https://bugzilla.kernel.org/show_bug.cgi?id=57271
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References: https://bugzilla.kernel.org/attachment.cgi?id=126801
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Suggested-by: Juan Manuel Cabo <juanmanuel.cabo@gmail.com>
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Signed-off-by: Kieran Clancy <clancy.kieran@gmail.com>
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Reviewed-by: Lan Tianyu <tianyu.lan@intel.com>
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Reviewed-by: Dennis Jansen <dennis.jansen@web.de>
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Tested-by: Kieran Clancy <clancy.kieran@gmail.com>
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Tested-by: Juan Manuel Cabo <juanmanuel.cabo@gmail.com>
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Tested-by: Dennis Jansen <dennis.jansen@web.de>
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Tested-by: Maurizio D'Addona <mauritiusdadd@gmail.com>
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Tested-by: San Zamoyski <san@plusnet.pl>
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Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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---
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diff --git a/drivers/acpi/ec.c b/drivers/acpi/ec.c
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index 959d41a..d7d32c2 100644
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--- a/drivers/acpi/ec.c
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+++ b/drivers/acpi/ec.c
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@@ -67,6 +67,8 @@ enum ec_command {
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#define ACPI_EC_DELAY 500 /* Wait 500ms max. during EC ops */
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#define ACPI_EC_UDELAY_GLK 1000 /* Wait 1ms max. to get global lock */
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#define ACPI_EC_MSI_UDELAY 550 /* Wait 550us for MSI EC */
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+#define ACPI_EC_CLEAR_MAX 100 /* Maximum number of events to query
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+ * when trying to clear the EC */
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enum {
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EC_FLAGS_QUERY_PENDING, /* Query is pending */
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@@ -116,6 +118,7 @@ EXPORT_SYMBOL(first_ec);
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static int EC_FLAGS_MSI; /* Out-of-spec MSI controller */
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static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
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static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
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+static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
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/* --------------------------------------------------------------------------
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Transaction Management
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@@ -440,6 +443,29 @@ acpi_handle ec_get_handle(void)
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EXPORT_SYMBOL(ec_get_handle);
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+static int acpi_ec_query_unlocked(struct acpi_ec *ec, u8 *data);
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+
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+/*
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+ * Clears stale _Q events that might have accumulated in the EC.
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+ * Run with locked ec mutex.
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+ */
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+static void acpi_ec_clear(struct acpi_ec *ec)
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+{
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+ int i, status;
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+ u8 value = 0;
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+
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+ for (i = 0; i < ACPI_EC_CLEAR_MAX; i++) {
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+ status = acpi_ec_query_unlocked(ec, &value);
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+ if (status || !value)
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+ break;
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+ }
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+
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+ if (unlikely(i == ACPI_EC_CLEAR_MAX))
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+ pr_warn("Warning: Maximum of %d stale EC events cleared\n", i);
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+ else
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+ pr_info("%d stale EC events cleared\n", i);
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+}
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+
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void acpi_ec_block_transactions(void)
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{
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struct acpi_ec *ec = first_ec;
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@@ -463,6 +489,10 @@ void acpi_ec_unblock_transactions(void)
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mutex_lock(&ec->mutex);
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/* Allow transactions to be carried out again */
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clear_bit(EC_FLAGS_BLOCKED, &ec->flags);
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+
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+ if (EC_FLAGS_CLEAR_ON_RESUME)
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+ acpi_ec_clear(ec);
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+
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mutex_unlock(&ec->mutex);
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}
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@@ -821,6 +851,13 @@ static int acpi_ec_add(struct acpi_device *device)
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/* EC is fully operational, allow queries */
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clear_bit(EC_FLAGS_QUERY_PENDING, &ec->flags);
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+
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+ /* Clear stale _Q events if hardware might require that */
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+ if (EC_FLAGS_CLEAR_ON_RESUME) {
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+ mutex_lock(&ec->mutex);
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+ acpi_ec_clear(ec);
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+ mutex_unlock(&ec->mutex);
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+ }
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return ret;
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}
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@@ -922,6 +959,30 @@ static int ec_enlarge_storm_threshold(const struct dmi_system_id *id)
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return 0;
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}
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+/*
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+ * On some hardware it is necessary to clear events accumulated by the EC during
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+ * sleep. These ECs stop reporting GPEs until they are manually polled, if too
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+ * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
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+ *
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+ * https://bugzilla.kernel.org/show_bug.cgi?id=44161
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+ *
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+ * Ideally, the EC should also be instructed NOT to accumulate events during
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+ * sleep (which Windows seems to do somehow), but the interface to control this
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+ * behaviour is not known at this time.
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+ *
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+ * Models known to be affected are Samsung 530Uxx/535Uxx/540Uxx/550Pxx/900Xxx,
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+ * however it is very likely that other Samsung models are affected.
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+ *
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+ * On systems which don't accumulate _Q events during sleep, this extra check
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+ * should be harmless.
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+ */
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+static int ec_clear_on_resume(const struct dmi_system_id *id)
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+{
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+ pr_debug("Detected system needing EC poll on resume.\n");
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+ EC_FLAGS_CLEAR_ON_RESUME = 1;
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+ return 0;
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+}
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+
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static struct dmi_system_id ec_dmi_table[] __initdata = {
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{
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ec_skip_dsdt_scan, "Compal JFL92", {
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@@ -965,6 +1026,9 @@ static struct dmi_system_id ec_dmi_table[] __initdata = {
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ec_validate_ecdt, "ASUS hardware", {
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DMI_MATCH(DMI_SYS_VENDOR, "ASUSTek Computer Inc."),
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DMI_MATCH(DMI_PRODUCT_NAME, "L4R"),}, NULL},
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+ {
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+ ec_clear_on_resume, "Samsung hardware", {
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+ DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
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{},
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};
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--
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cgit v0.9.2
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