This is a note to let you know that I've just added the patch titled

    ACPI / EC: Fix regression due to conflicting firmware behavior between 
Samsung and Acer.
 ACPI / EC: Add support to disallow QR_EC to be issued when SCI_EVT isn't set

to the 3.17-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     
acpi-ec-fix-regression-due-to-conflicting-firmware-behavior-between-samsung-and-acer.patch
and it can be found in the queue-3.17 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 79149001105f18bd2285ada109f9229ea24a7571 Mon Sep 17 00:00:00 2001
From: Lv Zheng <[email protected]>
Date: Wed, 29 Oct 2014 11:33:49 +0800
Subject: ACPI / EC: Fix regression due to conflicting firmware behavior between 
Samsung and Acer.
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

From: Lv Zheng <[email protected]>

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 <[email protected]>
Signed-off-by: Lv Zheng <[email protected]>
[ rjw : Subject ]
Signed-off-by: Rafael J. Wysocki <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/acpi/ec.c |   25 ++++++++++++++++++-------
 1 file changed, 18 insertions(+), 7 deletions(-)

--- a/drivers/acpi/ec.c
+++ b/drivers/acpi/ec.c
@@ -126,6 +126,7 @@ static int EC_FLAGS_MSI; /* Out-of-spec
 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
 static int EC_FLAGS_CLEAR_ON_RESUME; /* Needs acpi_ec_clear() on boot/resume */
+static int EC_FLAGS_QUERY_HANDSHAKE; /* Needs QR_EC issued when SCI_EVT set */
 
 /* --------------------------------------------------------------------------
                              Transaction Management
@@ -210,13 +211,8 @@ static bool advance_transaction(struct a
                }
                return wakeup;
        } else {
-               /*
-                * There is firmware refusing to respond QR_EC when SCI_EVT
-                * is not set, for which case, we complete the QR_EC
-                * without issuing it to the firmware.
-                * https://bugzilla.kernel.org/show_bug.cgi?id=86211
-                */
-               if (!(status & ACPI_EC_FLAG_SCI) &&
+               if (EC_FLAGS_QUERY_HANDSHAKE &&
+                   !(status & ACPI_EC_FLAG_SCI) &&
                    (t->command == ACPI_EC_COMMAND_QUERY)) {
                        t->flags |= ACPI_EC_COMMAND_POLL;
                        t->rdata[t->ri++] = 0x00;
@@ -981,6 +977,18 @@ static int ec_enlarge_storm_threshold(co
 }
 
 /*
+ * Acer EC firmware refuses to respond QR_EC when SCI_EVT is not set, for
+ * which case, we complete the QR_EC without issuing it to the firmware.
+ * https://bugzilla.kernel.org/show_bug.cgi?id=86211
+ */
+static int ec_flag_query_handshake(const struct dmi_system_id *id)
+{
+       pr_debug("Detected the EC firmware requiring QR_EC issued when SCI_EVT 
set\n");
+       EC_FLAGS_QUERY_HANDSHAKE = 1;
+       return 0;
+}
+
+/*
  * On some hardware it is necessary to clear events accumulated by the EC 
during
  * sleep. These ECs stop reporting GPEs until they are manually polled, if too
  * many events are accumulated. (e.g. Samsung Series 5/9 notebooks)
@@ -1054,6 +1062,9 @@ static struct dmi_system_id ec_dmi_table
        {
        ec_clear_on_resume, "Samsung hardware", {
        DMI_MATCH(DMI_SYS_VENDOR, "SAMSUNG ELECTRONICS CO., LTD.")}, NULL},
+       {
+       ec_flag_query_handshake, "Acer hardware", {
+       DMI_MATCH(DMI_SYS_VENDOR, "Acer"), }, NULL},
        {},
 };
 


Patches currently in stable-queue which might be from [email protected] are

queue-3.17/acpi-ec-fix-regression-due-to-conflicting-firmware-behavior-between-samsung-and-acer.patch
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