1 files changed, 24 insertions, 1 deletions

diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c b/drivers/media/dvb/dvb-core/dvb_frontend.c
index 39696c6a4ed7..0f64d7182657 100644
--- a/drivers/media/dvb/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb/dvb-core/dvb_frontend.c
@@ -1446,6 +1446,28 @@ static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
                                 __func__);
                         return -EINVAL;
                 }
+                /*
+                 * Get a delivery system that is compatible with DVBv3
+                 * NOTE: in order for this to work with softwares like Kaffeine that
+                 *      uses a DVBv5 call for DVB-S2 and a DVBv3 call to go back to
+                 *      DVB-S, drivers that support both should put the SYS_DVBS entry
+                 *      before the SYS_DVBS2, otherwise it won't switch back to DVB-S.
+                 *      The real fix is that userspace applications should not use DVBv3
+                 *      and not trust on calling FE_SET_FRONTEND to switch the delivery
+                 *      system.
+                 */
+                ncaps = 0;
+                while (fe->ops.delsys[ncaps] && ncaps < MAX_DELSYS) {
+                        if (fe->ops.delsys[ncaps] == desired_system) {
+                                delsys = desired_system;
+                                break;
+                        }
+                        ncaps++;
+                }
+                if (delsys == SYS_UNDEFINED) {
+                        dprintk("%s() Couldn't find a delivery system that matches %d\n",
+                                __func__, desired_system);
+                }
         } else {
                 /*
                  * This is a DVBv5 call. So, it likely knows the supported
@@ -1494,9 +1516,10 @@ static int set_delivery_system(struct dvb_frontend *fe, u32 desired_system)
                                 __func__);
                         return -EINVAL;
                 }
-                c->delivery_system = delsys;
         }
 
+        c->delivery_system = delsys;
+
         /*
          * The DVBv3 or DVBv5 call is requesting a different system. So,
          * emulation is needed.