don't allow 0 in ioctl to clear earlier CSI14t response #2000

src/lib/notcurses.c

@@ -266,9 +266,14 @@ int update_term_dimensions(int fd, int* rows, int* cols, tinfo* tcache,
     if(tcache->linux_fb_fd >= 0){
       get_linux_fb_pixelgeom(tcache, &tcache->pixy, &tcache->pixx);
     }else{
+      // we might have the pixel geometry from CSI14t, so don't override a
+      // valid earlier response with 0s from the ioctl. we do want to fire
+      // off a fresh CSI14t in this case, though FIXME.
+      if(ws.ws_ypixel){
         tcache->pixy = ws.ws_ypixel;
         tcache->pixx = ws.ws_xpixel;
       }
+    }
     tcache->cellpixy = ws.ws_row ? tcache->pixy / ws.ws_row : 0;
     tcache->cellpixx = ws.ws_col ? tcache->pixx / ws.ws_col : 0;
     if(tcache->cellpixy == 0 || tcache->cellpixx == 0){