VESA BIOS extensions: Do not list a linear framebuffer address if the…

… ModeAttributes does not say there is an LFB. Specifically, do not indicate a LFB for 4bpp planar modes and do not list a linear framebuffer address for 4bpp modes
joncampbell123 · Jan 12, 2025 · f9c17c0 · f9c17c0
1 parent c082b29
commit f9c17c0
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/src/ints/int10_vesa.cpp b/src/ints/int10_vesa.cpp
@@ -504,7 +504,8 @@ uint8_t VESA_GetSVGAModeInformation(uint16_t mode,uint16_t seg,uint16_t off) {
 		}
 	}
 
-	if (!int10.vesa_nolfb && !int10.vesa_oldvbe) var_write(&minfo.PhysBasePtr,S3_LFB_BASE + adj + (hack_lfb_yadjust*(long)host_readw((HostPt)(&minfo.BytesPerScanLine))));
+	if (!int10.vesa_nolfb && !int10.vesa_oldvbe && (modeAttributes&0x80)/*ModeAttributes indicates an LFB*/)
+		var_write(&minfo.PhysBasePtr,S3_LFB_BASE + adj + (hack_lfb_yadjust*(long)host_readw((HostPt)(&minfo.BytesPerScanLine))));
 
 	MEM_BlockWrite(buf,&minfo,sizeof(MODE_INFO));
 	return VESA_SUCCESS;