pixma: add button support for CanoScan LiDE400

backend/pixma_mp150.c

@@ -1021,6 +1021,14 @@ handle_interrupt (pixma_t * s, int timeout)
     if (buf[7] & 2)
       s->events = PIXMA_EV_BUTTON2 | buf[11] | buf[10]<<8 | buf[12]<<16;    /* b/w scan */
   }
+  else if (s->cfg->pid == LIDE400_PID)
+  /* unknown value in buf[4]
+   * target in buf[0x13]
+   * always set button-1 */
+  {
+    if (buf[0x13])
+      s->events = PIXMA_EV_BUTTON1 | buf[0x13];
+  }
   else
   /* button no. in buf[0]
    * original in buf[0]

doc/descriptions/pixma.desc

@@ -1298,5 +1298,5 @@
 :model "CanoScan LiDE 400"
 :interface "USB"
 :usbid "0x04a9" "0x1912"
-:status :good
-:comment "Support up to 4800DPI (Note: does not have less than 300DPI support, buttons not working)"
+:status :complete
+:comment "Support up to 4800DPI (Note: does not have less than 300DPI support)"