Add more comments for thunk call.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@7836 6f19259b-4bc3-4df7-8a09-765794883524

diff --git a/DuetPkg/BiosVideoThunkDxe/BiosVideo.c b/DuetPkg/BiosVideoThunkDxe/BiosVideo.c
index 2a3c41aefb551d26f7b1673e762abc50a380255e..07a20aeb000614fa5fb22ef6c1143eb30c031015 100644 (file)
--- a/DuetPkg/BiosVideoThunkDxe/BiosVideo.c
+++ b/DuetPkg/BiosVideoThunkDxe/BiosVideo.c
@@ -1088,6 +1088,21 @@ BiosVideoCheckForVbe (
   //\r
   // Test to see if the Video Adapter is compliant with VBE 3.0\r
   //\r
+  // INT 10 - VESA SuperVGA BIOS (VBE) - GET SuperVGA INFORMATION\r
+  //\r
+  //   AX = 4F00h\r
+  //   ES:DI -> buffer for SuperVGA information (see #00077)\r
+  // Return: AL = 4Fh if function supported\r
+  //   AH = status\r
+  //       00h successful\r
+  //           ES:DI buffer filled\r
+  //       01h failed\r
+  //       ---VBE v2.0---\r
+  //       02h function not supported by current hardware configuration\r
+  //       03h function invalid in current video mode\r
+  // Desc:     determine whether VESA BIOS extensions are present and the capabilities\r
+  //     supported by the display adapter\r
+  //\r
   gBS->SetMem (&Regs, sizeof (Regs), 0);\r
   Regs.X.AX = VESA_BIOS_EXTENSIONS_RETURN_CONTROLLER_INFORMATION;\r
   gBS->SetMem (BiosVideoPrivate->VbeInformationBlock, sizeof (VESA_BIOS_EXTENSIONS_INFORMATION_BLOCK), 0);\r
@@ -1121,6 +1136,19 @@ BiosVideoCheckForVbe (
   //\r
   // Read EDID information\r
   //\r
+  // INT 10 - VESA VBE/DC (Display Data Channel) - READ EDID\r
+  //\r
+  //    AX = 4F15h\r
+  //    BL = 01h\r
+  //    CX = 0000h\r
+  //    DX = 0000h\r
+  //    ES:DI -> 128-byte buffer for EDID record (see #00127)\r
+  // Return: AL = 4Fh if function supported\r
+  //    AH = status\r
+  //        00h successful\r
+  //    ES:DI buffer filled\r
+  //    01h failed (e.g. non-DDC monitor)\r
+  //\r
   gBS->SetMem (&Regs, sizeof (Regs), 0);\r
   Regs.X.AX = VESA_BIOS_EXTENSIONS_EDID;\r
   Regs.X.BX = 1;\r
@@ -1202,6 +1230,18 @@ BiosVideoCheckForVbe (
     //\r
     // Get the information about the mode\r
     //\r
+    // INT 10 - VESA SuperVGA BIOS - GET SuperVGA MODE INFORMATION\r
+    //\r
+    //  AX = 4F01h\r
+    //  CX = SuperVGA video mode (see #04082 for bitfields)\r
+    //  ES:DI -> 256-byte buffer for mode information (see #00079)\r
+    // Return: AL = 4Fh if function supported\r
+    //  AH = status\r
+    //     00h successful\r
+    //         ES:DI buffer filled\r
+    //     01h failed\r
+    // Desc:   determine the attributes of the specified video mode\r
+    //\r
     gBS->SetMem (&Regs, sizeof (Regs), 0);\r
     Regs.X.AX = VESA_BIOS_EXTENSIONS_RETURN_MODE_INFORMATION;\r
     Regs.X.CX = *ModeNumberPtr;\r