workaround painful vm86_datacall requirement that segment+offset

must be withing the same PAGE frame

1 files changed, 14 insertions, 5 deletions

diff --git a/sys/i386/isa/vesa.c b/sys/i386/isa/vesa.c
index fbd83a7..e03c714 100644
--- a/sys/i386/isa/vesa.c
+++ b/sys/i386/isa/vesa.c
@@ -23,7 +23,7 @@
  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
- * $Id: vesa.c,v 1.2 1998/09/23 09:59:00 yokota Exp $
+ * $Id: vesa.c,v 1.3 1998/09/25 11:55:46 yokota Exp $
  */
 
 #include "sc.h"
@@ -327,10 +327,13 @@ vesa_translate_flags(u_int16_t vflags)
 static int
 vesa_bios_init(void)
 {
-	static u_char buf[512];
+#define VESA_INFO_SIZE 512
+	static u_char buffer[VESA_INFO_SIZE * 2];
+	static u_char *buf = buffer;
 	struct vm86frame vmf;
 	struct vesa_mode vmode;
 	u_int32_t p;
+	u_short offset;
 	int modes;
 	int err;
 	int i;
@@ -343,10 +346,16 @@ vesa_bios_init(void)
 	vesa_vmode[0].vi_mode = EOT;
 
 	bzero(&vmf, sizeof(vmf));	/* paranoia */
-	bzero(buf, sizeof(buf));
-	bcopy("VBE2", buf, 4);		/* try for VBE2 data */
+	bzero(buffer, sizeof(buffer));
 	vmf.vmf_eax = 0x4f00;
-	err = vm86_datacall(0x10, &vmf, (char *)buf, sizeof(buf), 
+
+	/* workaround - see vm86.c:vm86_datacall */
+	offset = (u_int)buf & PAGE_MASK;
+	if ((offset + VESA_INFO_SIZE) & PG_FRAME)
+		buf += PAGE_SIZE - offset;
+
+	bcopy("VBE2", buf, 4);		/* try for VBE2 data */
+	err = vm86_datacall(0x10, &vmf, (char *)buf, VESA_INFO_SIZE,
 			  &vmf.vmf_es, &vmf.vmf_di);
 	if ((err != 0) || (vmf.vmf_eax != 0x4f) || bcmp("VESA", buf, 4))
 		return 1;