CUPS: Fix lpoptions file not being taken into account

This is actually two fixes.
 * We need to call cupsMarkOptions
 * CUPS differentiates between the "" and the nullptr instance, so we need
   to change the call to cupsGetNamedDest accordingly

Change-Id: If2692e405b6b71f8ee91362e6e72eabd9202d704
Reviewed-by: Liang Qi <liang.qi@qt.io>
Reviewed-by: Frederik Gladhorn <frederik.gladhorn@qt.io>

1 files changed, 2 insertions, 1 deletions

diff --git a/src/plugins/printsupport/cups/qppdprintdevice.cpp b/src/plugins/printsupport/cups/qppdprintdevice.cpp
index ad829df23d..021d040ad0 100644
--- a/src/plugins/printsupport/cups/qppdprintdevice.cpp
+++ b/src/plugins/printsupport/cups/qppdprintdevice.cpp
@@ -473,7 +473,7 @@ void QPpdPrintDevice::loadPrinter()
     }
 
     // Get the print instance and PPD file
-    m_cupsDest = cupsGetNamedDest(CUPS_HTTP_DEFAULT, m_cupsName, m_cupsInstance);
+    m_cupsDest = cupsGetNamedDest(CUPS_HTTP_DEFAULT, m_cupsName, m_cupsInstance.isNull() ? nullptr : m_cupsInstance.constData());
     if (m_cupsDest) {
         const char *ppdFile = cupsGetPPD(m_cupsName);
         if (ppdFile) {
@@ -482,6 +482,7 @@ void QPpdPrintDevice::loadPrinter()
         }
         if (m_ppd) {
             ppdMarkDefaults(m_ppd);
+            cupsMarkOptions(m_ppd, m_cupsDest->num_options, m_cupsDest->options);
         } else {
             cupsFreeDests(1, m_cupsDest);
             m_cupsDest = 0;