Re: Scanning for TV channels over DVB-T and DVB-T2

[Marc Gonzalez]

On 10/06/2020 17:22, Marc Gonzalez wrote:

> FTR, on IRC, Brad pointed out this patch of his:
> https://patchwork.kernel.org/patch/10744999/

I suggest the following patch on top of Brad's patch:

Author: Marc Gonzalez <marc.w.gonza...@free.fr>
Date:   Fri Jun 19 22:09:26 2020 +0200

    si2168: wait for carrier lock before next step

diff --git a/drivers/media/dvb-frontends/si2168.c 
b/drivers/media/dvb-frontends/si2168.c
index 31d3dc0216c2..e127e842f671 100644
--- a/drivers/media/dvb-frontends/si2168.c
+++ b/drivers/media/dvb-frontends/si2168.c
@@ -152,6 +152,11 @@ static int si2168_ts_bus_ctrl(struct dvb_frontend *fe, int 
acquire)
        return ret;
 }
 
+static bool carrier_locked(struct si2168_cmd *cmd)
+{
+       return cmd->args[2] & BIT(1);
+}
+
 static int si2168_read_status(struct dvb_frontend *fe, enum fe_status *status)
 {
        struct i2c_client *client = fe->demodulator_priv;
@@ -180,6 +185,9 @@ static int si2168_read_status(struct dvb_frontend *fe, enum 
fe_status *status)
                if (ret)
                        goto err;
 
+               if (!carrier_locked(&cmd))
+                       goto parse_response;
+
                if ((cmd.args[3] & 0x0f) == 7)
                        sys = SYS_DVBT2;
        }
@@ -206,27 +214,10 @@ static int si2168_read_status(struct dvb_frontend *fe, 
enum fe_status *status)
        }
 
        ret = si2168_cmd_execute(client, &cmd);
-       if (dvbt_auto_plp && (ret == -EREMOTEIO)) {
-               /* In auto-PLP mode it is possible to read 0x8701 while
-                * the frontend is in switchover transition. This causes
-                * a status read failure, due to incorrect system. Check
-                * the other sys if we hit this race condition.
-                */
-               if (sys == SYS_DVBT) {
-                       memcpy(cmd.args, "\x50\x01", 2); /* DVB-T2 */
-                       cmd.wlen = 2;
-                       cmd.rlen = 14;
-                       ret = si2168_cmd_execute(client, &cmd);
-               } else if (sys == SYS_DVBT2) {
-                       memcpy(cmd.args, "\xa0\x01", 2); /* DVB-T */
-                       cmd.wlen = 2;
-                       cmd.rlen = 13;
-                       ret = si2168_cmd_execute(client, &cmd);
-               }
-       }
        if (ret)
                goto err;
 
+parse_response:
        switch ((cmd.args[2] >> 1) & 0x03) {
        case 0x01:
                *status = FE_HAS_SIGNAL | FE_HAS_CARRIER;