graphics: report video mode change from protected-mode code

Syslinux used to call __intcall() for calling routines of the old
COMBOOT API to report video mode change (INT 22h, AX=0x0017) that seemed
pointless, since INT 22h, AX=0x0017 does call the protected-mode
function pm_using_vga() already when calling INT 22h, AX=0x0017. So for
reporting video mode changes (VGA in this case) we must call
graphics_using_vga() instead for now.

Signed-off-by: Paulo Alcantara <pcacjr@zytor.com>

5 files changed, 61 insertions, 20 deletions

diff --git a/com32/mboot/initvesa.c b/com32/mboot/initvesa.c
index cf2707df..bb3a8467 100644
--- a/com32/mboot/initvesa.c
+++ b/com32/mboot/initvesa.c
@@ -38,6 +38,7 @@
 #include <stdlib.h>
 #include <string.h>
 #include <limits.h>
+#include <graphics.h>
 
 #include "vesa.h"
 #include "mboot.h"
@@ -211,16 +212,12 @@ void set_graphics_mode(const struct multiboot_header *mbh,
 	mbi->vbe_interface_len = rm.ecx.w[0];
     }
 
-    /* Tell syslinux we changed video mode */
-    rm.eax.w[0] = 0x0017;	/* Report video mode change */
     /* In theory this should be:
-
-       rm.ebx.w[0] = (mi->mode_attr & 4) ? 0x0007 : 0x000f;
-
-       However, that would assume all systems that claim to handle text
-       output in VESA modes actually do that... */
-    rm.ebx.w[0] = 0x000f;
-    rm.ecx.w[0] = vesa_info.mi.h_res;
-    rm.edx.w[0] = vesa_info.mi.v_res;
-    __intcall(0x22, &rm, NULL);
+     *
+     * UsingVga = (mi->mode_attr & 4) ? 0x0007 : 0x000f;
+     *
+     * However, that would assume all systems that claim to handle text
+     * output in VESA modes actually do that...
+     */
+    graphics_using_vga(0x0F, vesa_info.mi.h_res, vesa_info.mi.v_res);
 }
diff --git a/core/comboot.inc b/core/comboot.inc
index 35cc91cf..83f0c030 100644
--- a/core/comboot.inc
+++ b/core/comboot.inc
@@ -654,7 +654,7 @@ comapi_usingvga:
 		ja .error
 		mov cx,P_CX
 		mov dx,P_DX
-		pm_call pm_usingvga
+		pm_call pm_using_vga
 		clc
 		ret
 .error:
diff --git a/core/extern.inc b/core/extern.inc
index da3d894b..f6ec0aec 100644
--- a/core/extern.inc
+++ b/core/extern.inc
@@ -64,13 +64,13 @@
 	extern pm_writehex2, pm_writehex4, pm_writehex8
 
 	; graphics.c
-	extern vgaclearmode, vgashowcursor, vgahidecursor
+	extern vgaclearmode, vgashowcursor, vgahidecursor, pm_using_vga
 
 	; conio.c
 	extern pm_pollchar, pm_write_serial, pm_serialcfg
 
 	; font.c
-	extern pm_getchar, pm_adjust_screen, pm_usingvga, pm_userfont
+	extern pm_getchar, pm_adjust_screen, pm_userfont
 
 	; localboot.c
 	extern pm_local_boot
diff --git a/core/graphics.c b/core/graphics.c
index 42ff6ec9..080efa11 100644
--- a/core/graphics.c
+++ b/core/graphics.c
@@ -354,12 +354,17 @@ void vgashowcursor(void)
 	vgacursorcommon('_');
 }
 
-void pm_usingvga(com32sys_t *regs)
+void using_vga(uint8_t vga, uint16_t pix_cols, uint16_t pix_rows)
 {
-	UsingVGA = regs->eax.b[0];
-	GXPixCols = regs->ecx.w[0];
-	GXPixRows = regs->edx.w[0];
+    UsingVGA = vga;
+    GXPixCols = pix_cols;
+    GXPixRows = pix_rows;
 
-	if (!(UsingVGA & 0x08))
-		adjust_screen();
+    if (!(UsingVGA & 0x08))
+        adjust_screen();
+}
+
+void pm_using_vga(com32sys_t *regs)
+{
+    using_vga(regs->eax.b[0], regs->ecx.w[0], regs->edx.w[0]);
 }
diff --git a/core/include/graphics.h b/core/include/graphics.h
new file mode 100644
index 00000000..0e4e005d
--- /dev/null
+++ b/core/include/graphics.h
@@ -0,0 +1,39 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2012 Paulo Alcantara <pcacjr@zytor.com>
+ *
+ *   Permission is hereby granted, free of charge, to any person
+ *   obtaining a copy of this software and associated documentation
+ *   files (the "Software"), to deal in the Software without
+ *   restriction, including without limitation the rights to use,
+ *   copy, modify, merge, publish, distribute, sublicense, and/or
+ *   sell copies of the Software, and to permit persons to whom
+ *   the Software is furnished to do so, subject to the following
+ *   conditions:
+ *
+ *   The above copyright notice and this permission notice shall
+ *   be included in all copies or substantial portions of the Software.
+ *
+ *   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ *   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
+ *   OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ *   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
+ *   HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
+ *   WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ *   FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
+ *   OTHER DEALINGS IN THE SOFTWARE.
+ *
+ * ----------------------------------------------------------------------- */
+
+#ifndef GRAPHICS_H_
+#define GRAPHICS_H_
+
+extern void using_vga(uint8_t vga, uint16_t pix_cols, uint16_t pix_rows);
+
+static inline void graphics_using_vga(uint8_t vga, uint16_t pix_cols,
+                                      uint16_t pix_rows)
+{
+    using_vga(vga, pix_cols, pix_rows);
+}
+
+#endif /* GRAPHICS_H_ */