V4L/DVB (12686): dvb-core: check supported QAM modulations

Check the modulation in dvb_frontend_check_parameters against
frontend's capabilties for FE_QAM devices.

Signed-off-by: Janne Grunau <j@jannau.net>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/media/dvb/dvb-core/dvb_frontend.c b/drivers/media/dvb/dvb-core/dvb_frontend.c
index 0cb6c09719f2..d13ebcb0c6b6 100644
--- a/drivers/media/dvb/dvb-core/dvb_frontend.c
+++ b/drivers/media/dvb/dvb-core/dvb_frontend.c
@@ -838,6 +838,15 @@ static int dvb_frontend_check_parameters(struct dvb_frontend *fe,
                 }
         }
 
+        /* check for supported modulation */
+        if (fe->ops.info.type == FE_QAM &&
+            (parms->u.qam.modulation > QAM_AUTO ||
+             !((1 << (parms->u.qam.modulation + 10)) & fe->ops.info.caps))) {
+                printk(KERN_WARNING "DVB: adapter %i frontend %i modulation %u not supported\n",
+                       fe->dvb->num, fe->id, parms->u.qam.modulation);
+                        return -EINVAL;
+        }
+
         return 0;
 }