[PATCH] Lower required VBE version from 2.0 to 1.2

Evgeny M. Zubok evgeny.zubok at tochka.ru
Tue May 19 07:10:53 PDT 2009

"Evgeny M. Zubok" <evgeny.zubok at tochka.ru> writes:

> So I conclude that the VBE version in vbeDoEDID can be lowered to 1.2
> as soon as the procedure for verifying the presence of subfunction
> (15h in the case of DDC) is defined in VESA 1.2 and VESA 2.0 specs.

If my arguments are right then the attached patch may be applied to
lower VBE version from 2.0 to 1.2. I tested this patch and successfully
retrieved EDID from my monitor through the xserver's VBE/DDC functions
and got the required modes.

diff --git a/hw/xfree86/vbe/vbe.c b/hw/xfree86/vbe/vbe.c
index 4986b5b..0f03a07 100644
--- a/hw/xfree86/vbe/vbe.c
+++ b/hw/xfree86/vbe/vbe.c
@@ -314,7 +314,7 @@ vbeDoEDID(vbeInfoPtr pVbe, pointer pDDCModule)
     unsigned char *DDC_data = NULL;
     if (!pVbe) return NULL;
-    if (pVbe->version < 0x200)
+    if (pVbe->version < 0x102)
        return NULL;
     if (!(pModule = pDDCModule)) {

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