[linux-dvb] [PATCH] Improve behaviour of scan app when setting frontend params

[Jon Burgess]

I have attached two small patches to the scan application, the first 
(scan-check-fe.diff) adds a check to report an error if there was a 
problem setting the frontend parameters.

The second patch (scan-fallback.diff) queries the frontend capabilities 
before trying to use "INVERSION_AUTO". I agree that this might not be 
the best place to do this, but it works for me.

It looks like a good place to add the software auto-inversion might be 
in the generic dvb-frontend code, thereby allowing it to be used by any 
tuner which doesn't have the hardware suport feature. I'll take a look 
when I get some more time.

	Jon
--- scan.c      Sat Jun  7 12:53:37 2003
+++ new/scan.c-check-fe Sat Jun  7 21:58:44 2003
@@ -1181,7 +1181,11 @@
                        p.frequency -= LOF_LO;
        }
 
-       ioctl(frontend_fd, FE_SET_FRONTEND, &p);
+       if (ioctl(frontend_fd, FE_SET_FRONTEND, &p) < 0)
+         {
+           MSG("ERROR: Setting frontend parameters failed");
+           return -1;
+         }
 
        for (i=0; i<3; i++) {
                fe_status_t s;
--- new/scan.c-check-fe Sat Jun  7 21:58:44 2003
+++ new/scan.c-fallback Sat Jun  7 21:58:44 2003
@@ -1152,6 +1152,7 @@
 static
 int __tune_to_transponder (int frontend_fd, struct transponder *t)
 {
+       struct dvb_frontend_info fe_info;
        struct dvb_frontend_parameters p;
        int i;
 
@@ -1179,6 +1180,16 @@
                        p.frequency -= LOF_HI;
                else
                        p.frequency -= LOF_LO;
+       }
+
+       /* Verify requested parameters are within frontend capabilities */
+       ioctl(frontend_fd, FE_GET_INFO, &fe_info);
+
+       if ((p.inversion == INVERSION_AUTO ) && 
+           !(fe_info.caps & FE_CAN_INVERSION_AUTO))
+       {
+           MSG("Frontend can not do requested INVERSION_AUTO, trying INVERSION_OFF 
instead");
+           p.inversion = INVERSION_OFF;
        }
 
        if (ioctl(frontend_fd, FE_SET_FRONTEND, &p) < 0)