Add comments to explain the reason return status is not checked. The return status...

[mirror_edk2.git] / IntelFrameworkModulePkg / Bus / Isa / Ps2KeyboardDxe / Ps2Keyboard.c

diff --git a/IntelFrameworkModulePkg/Bus/Isa/Ps2KeyboardDxe/Ps2Keyboard.c b/IntelFrameworkModulePkg/Bus/Isa/Ps2KeyboardDxe/Ps2Keyboard.c
index 0b4aff77903fe5832a2fb46b5d90134d96529c7b..c73cf936131830a75148cc95550ce7ed2f6a6b5d 100644 (file)
--- a/IntelFrameworkModulePkg/Bus/Isa/Ps2KeyboardDxe/Ps2Keyboard.c
+++ b/IntelFrameworkModulePkg/Bus/Isa/Ps2KeyboardDxe/Ps2Keyboard.c
@@ -255,6 +255,13 @@ KbdControllerDriverStart (
 \r
   //\r
   // Fix for random hangs in System waiting for the Key if no KBC is present in BIOS.\r
+  // When KBC decode (IO port 0x60/0x64 decode) is not enabled, \r
+  // KeyboardRead will read back as 0xFF and return status is EFI_SUCCESS.\r
+  // So instead we read status register to detect after read if KBC decode is enabled.\r
+  //\r
+  \r
+  //\r
+  // Return code is ignored on purpose.\r
   //\r
   KeyboardRead (ConsoleIn, &Data);\r
   if ((KeyReadStatusRegister (ConsoleIn) & (KBC_PARE | KBC_TIM)) == (KBC_PARE | KBC_TIM)) {\r