bootloader: Check that VESA mode is linear

I don't think there are any graphical non-linear framebuffers but good to be sure
2026-07-20 04:07:23 +03:00
parent 9bdf60bb88
commit 658e74b507
1 changed files with 5 additions and 3 deletions
@@ -108,9 +108,11 @@ vesa_find_video_mode:
 	cmpb $0x4F, %al; jne .vesa_unsupported
 	cmpb $0x00, %ah; jne .vesa_error

-	# check whether in graphics mode
-	testb $0x10, (vesa_mode_info_buffer + 0)
-	jz .vesa_find_video_mode_next_mode
+	# check whether in graphics mode and linear framebuffer
+	movb (vesa_mode_info_buffer + 0), %al
+	andb $(0x80 | 0x10), %al
+	cmpb $(0x80 | 0x10), %al
+	jne .vesa_find_video_mode_next_mode

 	# compare mode's dimensions
 	movw -2(%ebp), %ax; cmpw %ax, (vesa_mode_info_buffer + 0x12)