[edk2-devel][edk2-platforms][PATCH v1 3/7] KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi: Improvements for EC ACPI

["Benjamin Doron" <benjamin.doron00@gmail.com>]

Perform EC read and write via SystemIO when EmbeddedControl is
unavailable. Not properly tested yet.

Re-sync against coreboot port.

Does not yet handle SMM traps. In-progress.

Cc: Sai Chaganty <rangasai.v.chaganty@intel.com>
Cc: Isaac Oram <isaac.w.oram@intel.com>
Cc: Nate DeSimone <nathaniel.l.desimone@intel.com>
Cc: Chasel Chiu <chasel.chiu@intel.com>
Signed-off-by: Benjamin Doron <benjamin.doron00@gmail.com>
---
 .../Acpi/BoardAcpiTables.inf                  |   4 +
 .../AspireVn7Dash572G/Acpi/BoardSsdt.asl      |  29 +++-
 .../AspireVn7Dash572G/Acpi/battery.asl        |  11 +-
 .../AspireVn7Dash572G/Acpi/ec.asl             | 130 ++++++++--------
 .../AspireVn7Dash572G/Acpi/eclib.asl          | 141 ++++++++++++++++++
 .../AspireVn7Dash572G/Acpi/mainboard.asl      |   6 +-
 .../AspireVn7Dash572G/Acpi/thermal.asl        |  16 +-
 7 files changed, 256 insertions(+), 81 deletions(-)
 create mode 100644 Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/eclib.asl

diff --git a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/BoardAcpiTables.inf b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/BoardAcpiTables.inf
index 806c0d2575c8..9a31b400a35e 100644
--- a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/BoardAcpiTables.inf
+++ b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/BoardAcpiTables.inf
@@ -13,5 +13,9 @@
   MODULE_TYPE          = USER_DEFINED
   VERSION_STRING       = 1.0
 
+[Packages]
+  KabylakeOpenBoardPkg/OpenBoardPkg.dec
+  MdePkg/MdePkg.dec
+
 [Sources]
   BoardSsdt.asl
diff --git a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/BoardSsdt.asl b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/BoardSsdt.asl
index cdec0434883e..d1609131ecf7 100644
--- a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/BoardSsdt.asl
+++ b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/BoardSsdt.asl
@@ -6,17 +6,44 @@
 
 **/
 
+#include <IndustryStandard/Acpi63.h>
+
 DefinitionBlock (
   "Board.aml",
   "SSDT",
-  0x02,
+  EFI_ACPI_6_3_DIFFERENTIATED_SYSTEM_DESCRIPTION_TABLE_REVISION,
   "ACRSKL",
   "AcerSKL ",
   0x20141018
   )
 {
+  External (SSMP, IntObj)
+  External (SMIF, IntObj)
   External (\MDBG, MethodObj)
 
+  // SW SMI data port
+  OperationRegion (DPRT, SystemIO, 0xB3, 1)
+  Field (DPRT, ByteAcc, Lock, Preserve)
+  {
+    SSDP, 8
+  }
+
+  Name (ESMI, 0xDD)  // TODO: Patch at runtime
+  Method (TRPS, 3, Serialized)
+  {
+    \DBGH (Concatenate ("SMIF: ", ToHexString (Arg0)))
+    \DBGH (Concatenate ("Param0: ", ToHexString (Arg1)))
+    \DBGH (Concatenate ("Param1: ", ToHexString (Arg2)))
+
+    Local0 = Arg1
+    Local0 |= (Arg2 << 4)
+    \DBGH (Concatenate ("Local0: ", ToHexString (Local0)))
+
+    SMIF = Arg0
+    SSDP = Local0
+    SSMP = ESMI
+  }
+
   // Debug print helper
   Method (DBGH, 1)
   {
diff --git a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/battery.asl b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/battery.asl
index 5ae4bdca89d5..1bf652c4a01e 100644
--- a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/battery.asl
+++ b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/battery.asl
@@ -184,11 +184,17 @@ Method (GBIF, 3, NotSerialized)
     Local7 = EBSN
 #endif
     Name (SERN, Buffer (0x06) { "     " })
+    /* Convert hex to decimal.
+     * - There appears to be a bug in the vendor's implementation:
+     *   The correct answer has, or can have, 5 digits, so Local6 = 5.
+     *   Also see "SERN" buffer.
+     * - Userspace prints reversed serial number?
+     */
     Local6 = 4
     While (Local7)
     {
       Divide (Local7, 10, Local5, Local7)
-      SERN[Local6] = (Local5 + 0x30)  // Add ASCII 0x30 to get character
+      SERN[Local6] = (Local5 + 0x30)  // Add 0x30 to get numeric character
       Local6--
     }
 
@@ -310,7 +316,7 @@ Method (GBST, 4, NotSerialized)  // All on one page
     If (Arg2)
     {
       Local1 *= Local3
-      Local1 /= 1000  /* Remainder ignored */
+      Local1 /= 1000  /* Remainder ignored by vendor */
     }
   }
   Else
@@ -382,6 +388,7 @@ Device (BAT0)
 
   Method (_BIF, 0, NotSerialized)  // _BIF: Battery Information
   {
+    /* Bitwise AND by vendor is lossy? */
     Local6 = B0ST
     Local7 = 20
     While (Local6 && Local7)
diff --git a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/ec.asl b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/ec.asl
index df71dd69b491..b8f0dba1597f 100644
--- a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/ec.asl
+++ b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/ec.asl
@@ -5,18 +5,33 @@
 
 **/
 
-/* Global TODO: (externally: Optimus GC6 and GPS)
+/*
+ * Global TODO: (externally: Optimus GC6 and GPS)
  * - TRPS: This is SMI 0xDD, likely in SmmOemDriver. This SW SMI adds to and executes
  *         a table of function pointers produced throughout the OEM 'value-add' stack.
+ *         - Arg0 - "SFUN" - is index into "$FNC" pointer table? It's easier to
+ *           correlate *CommonService use: Offset 13 creates TRPS handlers.
+ *         - Known functions:
+ *           - 0x80 calls offset 0 in ACER_BOOT_DEVICE_SERVICE_PROTOCOL_GUID.
+ *             - NB: efiXplorer can miss InstallProtocolInterface() when Interface is local
+ *           - 0x81 toggles Intel Dynamic Acceleration in IA32_MISC_ENABLE MSR.
+ *           - 0x82 does switch on "OSYS" to set EC byte. Suspect this is for OS features.
+ *         (A CVE exists in the vendor code only if it never sets the offset in the buffer.)
+ * - RBEC/WBEC/MBEC: This is SMI 0xDD, "functions" 0x10, 0x11 and 0x12 in SmmKbcDriver,
+ *        added into SmmCommonService table at its protocol notify. Performs read, write
+ *        and read-modify-write from buffer. We will use ACPI instead.
  * - WMI: This is likely SMI 0xD0 in A01WMISmmCallback. This SW SMI likely uses the WMI
  *        object and consumes the OEM 'value-add' stack for EC and presumably the A01*
- *        OEM/ODM 'value-add' stack.
+ *        OEM/ODM 'value-add' stack. An SSDT contains the device and EC0 provides "GCMS"
+ *        and "GOTS" method helpers.
  *
- * Generally, more reversing is needed.
+ * Generally, more information is needed.
+ * TODO: Restore stripped features using reference code (except, check BoardAcpiDxe first)
+ *       and implement more board features: lid and touchpad trigger wake from S3,
+ *       Fn-Ctrl swap, sticky Fn keys and always-on USB charger.
  */
-/* TODO: Implement more features around reference code (except, check BoardAcpiDxe first) */
 
-// TODO: Enable and test
+// TODO/TEST
 #undef LGMR_ENABLED
 
 // "DIDX" - "DeviceIdX" is uninitialised, cannot use "BRTN" method yet
@@ -40,17 +55,7 @@ Device (\_SB.PCI0.LPCB.EC0)
     IO (Decode16, 0x66, 0x66, 0, 1)
   })
 
-  OperationRegion (ECO1, SystemIO, 0x62, 1)
-  Field (ECO1, ByteAcc, Lock, Preserve)
-  {
-    PX62, 8
-  }
-
-  OperationRegion (ECO2, SystemIO, 0x66, 1)
-  Field (ECO2, ByteAcc, Lock, Preserve)
-  {
-    PX66, 8
-  }
+  #include "eclib.asl"
 
 #ifdef LGMR_ENABLED
   OperationRegion (ECMB, SystemMemory, LGMR, 0x200)
@@ -84,10 +89,12 @@ Device (\_SB.PCI0.LPCB.EC0)
     EX3G, 1,        /* 3G */
         , 3,
     RFEX, 1,        /* RF present */
-#if 0  // Merely a guess
-    Offset (0x55),
-    BTH0, 8,        /* Battery threshold? TODO: Actually diff in modified vendor FW */
-#endif
+/*
+ * NOTE: Some reverse engineering, as well as corroborating vendor's hidden SetupUtility
+ * options with the EC's memory space, suggests that offset 0x55 might be the battery
+ * threshold
+ * - TODO: Actually diff changes in modified vendor FW
+ */
     Offset (0x57),
         , 7,
     AHKB, 1,        /* Hotkey triggered */
@@ -204,14 +211,19 @@ Device (\_SB.PCI0.LPCB.EC0)
       {
         TINI ()
         EOSS = 0x05
-//      OSIN ()
+        // OSYS retrieved by SMM, Arg3 is unused
+//      TRPS (0x82, 1, 0)
 
-        /* Other pages return valid data too, but this seems to be the page
+        /*
+         * Other pages return valid data too, but this seems to be the page
          * we are expecting - persistently in ectool dump with vendor firmware
-         * FIXME: Contents of other pages? */
+         * FIXME: Contents of other pages?
+         */
         ETID = 0x20
       }
     }
+
+    /* iGFX RC method call stripped */
   }
 
   Method (TINI, 0, NotSerialized)
@@ -223,10 +235,8 @@ Device (\_SB.PCI0.LPCB.EC0)
     }
     Else
     {
-      /* WBEC: Called SMI function 0x11 */
-//    EC_WRITE (0x92, 0)  // ETAF = 0
-      /* MBEC: Called SMI function 0x12 */
-//    MBEC (0x10, 0xFD, 0x02)  // ETEE = 1
+      WBEC (0x92, 0)  // ETAF = 0
+      MBEC (0x10, 0xFD, 0x02)  // ETEE = 1
     }
   }
 
@@ -234,10 +244,8 @@ Device (\_SB.PCI0.LPCB.EC0)
   Method (ECPS, 1, NotSerialized)  // _PTS: Prepare To Sleep
   {
     ECSS = Arg0
-//  COSI = OSYS
-//  SPR1 = Arg0
-    /* TRPS: Generic SMI trap handler */
-//  TRPS (0x82, 0x02)
+    // OSYS retrieved by SMM
+//  TRPS (0x82, 0x02, Arg0)
     If ((Arg0 == 3) || (Arg0 == 4))
     {
       RFST = RFEX
@@ -250,38 +258,23 @@ Device (\_SB.PCI0.LPCB.EC0)
     EOSS = Arg0
     TINI ()
     Notify (BAT0, 0x81) // Information Change
-//  COSI = OSYS
-//  SPR1 = Arg0
-    /* TRPS: Generic SMI trap handler */
-//  TRPS (0x82, 0x03)
+    // OSYS retrieved by SMM
+//  TRPS (0x82, 0x03, Arg0)
     If ((Arg0 == 3) || (Arg0 == 4))
     {
       RFEX = RFST
       Notify (SLPB, 0x02) // Device Wake
     }
+    /* iGFX RC method call stripped */
   }
 
-#if 0  // TODO: Figure out what this is for
-  Method (OSIN, 0, NotSerialized)
+  Method (MBEC, 3, Serialized)
   {
-    COSI = OSYS
-    /* TRPS: Generic SMI trap handler */
-    TRPS (0x82, 1)
-  }
-#endif
-
-#if 0  // TODO: Implement
-  Method (MBEC, 3, Serialized)  // Read-Modify-Write
-  {
-    /* Based on similar methods/tables at
-     * https://github.com/linuxhw/ACPI/blob/master/Notebook/Sony/SVE1713/SVE1713S1RW/506CDC50E671#L9359
-     * which use ASL instead of SMM calls */
-    Local0 = EC_READ (Arg0)
+    Local0 = RBEC (Arg0)
     Local0 &= Arg1
     Local0 |= Arg2
-    EC_WRITE (Arg0, Local0)
+    WBEC (Arg0, Local0)
   }
-#endif
 
   /* Graphical hotkey */
   Method (_Q19, 0, NotSerialized)
@@ -316,7 +309,8 @@ Device (\_SB.PCI0.LPCB.EC0)
         }
         ElseIf ((Local1 > 0x80) && (Local1 < 0xA0))
         {
-          TPEN ^= 1  /* TODO: Not working. What else does WMI do here? */
+          /* TODO: Not working when called by HID mode. What does WMI do here? */
+          TPEN ^= 1
         }
       }
     }
@@ -330,8 +324,7 @@ Device (\_SB.PCI0.LPCB.EC0)
     }
     Else
     {
-      /* MBEC: Called SMI function 0x12 */
-//    MBEC (0x92, 0xF7, 0x08)  // EOSD = 1
+      MBEC (0x92, 0xF7, 0x08)  // EOSD = 1
     }
 
     Sleep (500)
@@ -341,9 +334,8 @@ Device (\_SB.PCI0.LPCB.EC0)
 
   Method (_Q3F, 0, NotSerialized)
   {
-    \DBGH ("EC Query: 0x3F - TRPS")
-    /* TRPS: Generic SMI trap handler */
-//  TRPS (0x80, 0)
+    // Arg3 is unused
+//  TRPS (0x80, 0, 0)
   }
 
   Method (_Q40, 0, NotSerialized)
@@ -397,46 +389,44 @@ Device (\_SB.PCI0.LPCB.EC0)
 
   Method (_Q60, 0, NotSerialized)
   {
-    \DBGH ("EC Query: 0x60 -> WMI")
+    \DBGH ("EC Query (0x60): WMI")
   }
 
   Method (_Q61, 0, NotSerialized)
   {
-    \DBGH ("EC Query: 0x61 -> WMI")
+    \DBGH ("EC Query (0x61): WMI")
   }
 
   Method (_Q62, 0, NotSerialized)
   {
-    \DBGH ("EC Query: 0x62 -> Optimus GC6")
+    \DBGH ("EC Query (0x62): Optimus GC6 or NVIDIA GPS")
   }
 
   Method (_Q63, 0, NotSerialized)
   {
-    \DBGH ("EC Query: 0x63 -> Optimus GC6")
+    \DBGH ("EC Query (0x63): Optimus GC6 or NVIDIA GPS")
   }
 
   Method (_Q67, 0, NotSerialized)
   {
-    \DBGH ("EC Query: 0x67 -> NVIDIA GPS")
+    \DBGH ("EC Query (0x67): NVIDIA GPS")
   }
 
   Method (_Q68, 0, NotSerialized)
   {
-    \DBGH ("EC Query: 0x68 -> NVIDIA GPS")
+    \DBGH ("EC Query (0x68): NVIDIA GPS")
   }
 
   Method (_Q6C, 0, NotSerialized)
   {
-    \DBGH ("EC Query: 0x6C - TRPS")
-    /* TRPS: Generic SMI trap handler */
-//  TRPS (0x81, 0)
+    // Arg3 is unused
+//  TRPS (0x81, 0, 0)
   }
 
   Method (_Q6D, 0, NotSerialized)
   {
-    \DBGH ("EC Query: 0x6D - TRPS")
-    /* TRPS: Generic SMI trap handler */
-//  TRPS (0x81, 1)
+    // Arg3 is unused
+//  TRPS (0x81, 1, 0)
   }
 
   #include "ac.asl"
diff --git a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/eclib.asl b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/eclib.asl
new file mode 100644
index 000000000000..57921eb09c8b
--- /dev/null
+++ b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/eclib.asl
@@ -0,0 +1,141 @@
+/** @file
+  This file contains the EC library for ACPI.
+
+  Copyright (c) 2021, Baruch Binyamin Doron
+  SPDX-License-Identifier: BSD-2-Clause-Patent
+
+**/
+
+#include <EcCommands.h>
+
+Mutex (EMTX, 0)
+
+OperationRegion (ECO1, SystemIO, EC_D_PORT, 1)
+Field (ECO1, ByteAcc, Lock, Preserve)
+{
+  ECDT, 8
+}
+
+OperationRegion (ECO2, SystemIO, EC_C_PORT, 1)
+Field (ECO2, ByteAcc, Lock, Preserve)
+{
+  ECSC, 8
+}
+
+// Send EC command
+// Return time elapsed on success, EC_TIME_OUT on failure
+Method (SECC, 1, Serialized)
+{
+  // Wait EC timeout for input buffer to be empty
+  Local0 = 0
+  While ((ECSC & EC_S_IBF) && Local0 < EC_TIME_OUT)
+  {
+    Stall (1)
+    Local0++
+  }
+  // Send command if timeout was not reached
+  If (Local0 < EC_TIME_OUT)
+  {
+    ECSC = Arg0
+  }
+
+  // Return status
+  Return (Local0)
+}
+
+// Send EC data
+// Return time elapsed on success, EC_TIME_OUT on failure
+Method (SECD, 1, Serialized)
+{
+  // Wait EC timeout for input buffer to be empty
+  Local0 = 0
+  While ((ECSC & EC_S_IBF) && Local0 < EC_TIME_OUT)
+  {
+    Stall (1)
+    Local0++
+  }
+  // Send data if timeout was not reached
+  If (Local0 < EC_TIME_OUT)
+  {
+    ECDT = Arg0
+  }
+
+  // Return status
+  Return (Local0)
+}
+
+// Receive EC data
+// Return data on success, EC_TIME_OUT on failure
+Method (RECD, 0, Serialized)
+{
+  // Wait EC timeout for input buffer to be empty
+  Local0 = 0
+  While ((ECSC & EC_S_OBF) && Local0 < EC_TIME_OUT)
+  {
+    Stall (1)
+    Local0++
+  }
+  // Return data
+  If (Local0 < EC_TIME_OUT)
+  {
+    Return (ECDT)
+  }
+
+  // Timeout exceeded, return failure
+  Return (Local0)
+}
+
+// Read EC byte
+// Return data on success, EC_TIME_OUT on failure
+Method (RBEC, 1, Serialized)
+{
+  // Check for mutex acquired to not run with another function
+  Local0 = Acquire (EMTX, 0xFFFF)
+  If (Local0 == 0)
+  {
+    Local0 = SECC (EC_C_ACPI_READ)
+  }
+
+  If (Local0 < EC_TIME_OUT)
+  {
+    // Send address
+    Local0 = SECD (Arg0)
+  }
+
+  If (Local0 < EC_TIME_OUT)
+  {
+    // Receive data
+    Local0 = RECD ()
+  }
+
+  Release (EMTX)
+  Return (Local0)
+}
+
+// Write EC byte
+// Return time elapsed on success, EC_TIME_OUT on failure
+Method (WBEC, 2, Serialized)
+{
+  // Check for mutex acquired to not run with another function
+  Local0 = Acquire (EMTX, 0xFFFF)
+  If (Local0 == 0)
+  {
+    Local0 = SECC (EC_C_ACPI_READ)
+  }
+
+  If (Local0 < EC_TIME_OUT)
+  {
+    // Send address
+    Local0 = SECD (Arg0)
+  }
+
+  If (Local0 < EC_TIME_OUT)
+  {
+    // Send data
+    Local0 = SECD (Arg1)
+  }
+
+  Release (EMTX)
+  // Return data
+  Return (Local0)
+}
diff --git a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/mainboard.asl b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/mainboard.asl
index 7a73d37429d0..46edce92fb47 100644
--- a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/mainboard.asl
+++ b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/mainboard.asl
@@ -6,25 +6,27 @@
 **/
 
 // TODO: Add HID support for touchpad, etc.
+// - Does board actually support DPTF?
 #include "thermal.asl"
 
 External (\_SB.SLPB, DeviceObj)
 
-// TODO: Need hooks from BoardAcpiDxe
-
 Scope (_SB)
 {
   Method (MPTS, 1, NotSerialized)  // _PTS: Prepare To Sleep
   {
     ^PCI0.LPCB.EC0.ECPS (Arg0)
+    /* TBT and DTS not supported, TPM.PTS can be called elsewhere */
   }
 
   Method (MWAK, 1, Serialized)  // _WAK: Wake
   {
     ^PCI0.LPCB.EC0.ECWK (Arg0)
+    /* No GPIO expander, 8254 clock-gating and PCIe PME can be performed elsewhere */
 
     If ((Arg0 == 3) || (Arg0 == 4))
     {
+      /* DTS and TBT not supported, iGFX RC variable update stripped */
       Notify (LID0, 0x80) // Status Change
     }
   }
diff --git a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/thermal.asl b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/thermal.asl
index 805ee0700cd0..5d6604b41a9f 100644
--- a/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/thermal.asl
+++ b/Platform/Intel/KabylakeOpenBoardPkg/AspireVn7Dash572G/Acpi/thermal.asl
@@ -15,12 +15,16 @@ Scope (_TZ)
     {
 #ifdef LGMR_ENABLED
       Local0 = \_SB.PCI0.LPCB.EC0.MS0T
-//    Local1 = \_SB.PCI0.LPCB.EC0.MCSS
+      Local1 = \_SB.PCI0.LPCB.EC0.MCSS
+      /* Suppress warning over reading status flag by dummy OR */
+      Or (Local1, 1, Local1)
       Local2 = \_SB.PCI0.LPCB.EC0.MOSD
 #else
       Local0 = \_SB.PCI0.LPCB.EC0.ES0T
-//    Local1 = \_SB.PCI0.LPCB.EC0.ESSF  // "MCSS": Considering neighbouring bits, likely
-                                        // "ESSF" in thermals, not "ECSS" in notify
+      /* "MCSS": Considering neighbouring bits, likely
+       * "ESSF" in thermals, not "ECSS" in power notifications */
+      Local1 = \_SB.PCI0.LPCB.EC0.ESSF
+      Or (Local1, 1, Local1)
       Local2 = \_SB.PCI0.LPCB.EC0.EOSD
 #endif
       If (Local2)  // Thermal trip
@@ -59,7 +63,7 @@ Scope (_TZ)
       Else
       {
         /* MBEC: Called SMI function 0x12 */
-//      \_SB.PCI0.LPCB.EC0.MBEC (0x90, 0xFE, Arg0)  // SCPM = Arg0
+        \_SB.PCI0.LPCB.EC0.MBEC (0x90, 0xFE, Arg0)  // SCPM = Arg0
       }
     }
 
@@ -89,6 +93,7 @@ Scope (_TZ)
 #else
       Local0 = \_SB.PCI0.LPCB.EC0.ES1T
 #endif
+
       Return (C2K (Local0))
     }
 
@@ -116,7 +121,6 @@ Scope (_TZ)
       Local0 = 30
     }
 
-    Local0 = ((Local0 * 10) + 2732)  // Celsius to Kelvin
-    Return (Local0)
+    Return ((Local0 * 10) + 2732)  // Celsius to centi-Kelvin
   }
 }
-- 
2.37.2