vgabios: Avoid possible divide by zero in bochsvga_set_displaystart.

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

diff --git a/vgasrc/bochsvga.c b/vgasrc/bochsvga.c
index a19eccbb62dcfa9896bde69a637c6cf93a9ee708..6da9d5da129d28739c42af076a71ecc759b6772d 100644 (file)
--- a/vgasrc/bochsvga.c
+++ b/vgasrc/bochsvga.c
@@ -212,6 +212,8 @@ bochsvga_set_displaystart(struct vgamode_s *vmode_g, int val)
     if (GET_GLOBAL(dispi_found)) {
         int bpp = vga_bpp(vmode_g);
         int linelength = dispi_read(VBE_DISPI_INDEX_VIRT_WIDTH) * bpp / 8;
+        if (!linelength)
+            return 0;
         dispi_write(VBE_DISPI_INDEX_X_OFFSET, (val % linelength) * 8 / bpp);
         dispi_write(VBE_DISPI_INDEX_Y_OFFSET, val / linelength);
     }