Hi Mauro,

Just tried this on my card - unfortunately the patch as is doesn't work.

On 13/08/17 13:10, Mauro Carvalho Chehab wrote:
This Kaffeine's BZ:
        https://bugs.kde.org/show_bug.cgi?id=374693

affects SkyStar S2 PCI DVB-S/S2 rev 3.3 device. It could be due to
a Kernel bug.

While checking the Isil 6421, comparing with its manual, available at:

        http://www.intersil.com/content/dam/Intersil/documents/isl6/isl6421a.pdf

It was noticed that, if the output load is highly capacitive, a different 
approach
is recomended when energizing the LNBf.

Also, it is possible to detect if a current overload is happening, by checking 
an
special flag.

Add support for it.

Compile-tested only.

Signed-off-by: Mauro Carvalho Chehab <mche...@s-opensource.com>
---
  drivers/media/dvb-frontends/isl6421.c | 72 +++++++++++++++++++++++++++++++++--
  1 file changed, 68 insertions(+), 4 deletions(-)

diff --git a/drivers/media/dvb-frontends/isl6421.c 
b/drivers/media/dvb-frontends/isl6421.c
index 838b42771a05..47a7e559cef2 100644
--- a/drivers/media/dvb-frontends/isl6421.c
+++ b/drivers/media/dvb-frontends/isl6421.c
@@ -38,25 +38,43 @@ struct isl6421 {
        u8                      override_and;
        struct i2c_adapter      *i2c;
        u8                      i2c_addr;
+       bool                    is_off;
  };
static int isl6421_set_voltage(struct dvb_frontend *fe,
                               enum fe_sec_voltage voltage)
  {
+       int ret;
+       u8 buf;
+       bool is_off;
        struct isl6421 *isl6421 = (struct isl6421 *) fe->sec_priv;
-       struct i2c_msg msg = {  .addr = isl6421->i2c_addr, .flags = 0,
-                               .buf = &isl6421->config,
-                               .len = sizeof(isl6421->config) };
+       struct i2c_msg msg[2] = {
+               {
+                 .addr = isl6421->i2c_addr,
+                 .flags = 0,
+                 .buf = &isl6421->config,
+                 .len = 1,
+               }, {
+                 .addr = isl6421->i2c_addr,
+                 .flags = I2C_M_RD,
+                 .buf = &buf,
+                 .len = 1,
+               }
+
+       };
isl6421->config &= ~(ISL6421_VSEL1 | ISL6421_EN1); switch(voltage) {
        case SEC_VOLTAGE_OFF:
+               is_off = true;
                break;
        case SEC_VOLTAGE_13:
+               is_off = false;
                isl6421->config |= ISL6421_EN1;
                break;
        case SEC_VOLTAGE_18:
+               is_off = false;
                isl6421->config |= (ISL6421_EN1 | ISL6421_VSEL1);
                break;
        default:
@@ -66,7 +84,51 @@ static int isl6421_set_voltage(struct dvb_frontend *fe,
        isl6421->config |= isl6421->override_or;
        isl6421->config &= isl6421->override_and;
- return (i2c_transfer(isl6421->i2c, &msg, 1) == 1) ? 0 : -EIO;
+       /*
+        * If LNBf were not powered on, disable dynamic current limit, as,
+        * according with datasheet, highly capacitive load on the output may
+        * cause a difficult start-up.
+        */
+       if (isl6421->is_off && !is_off)
+               isl6421->config |= ISL6421_EN1;
+
+       ret = i2c_transfer(isl6421->i2c, msg, 2);
+       if (ret < 0)
+               return ret;
+       if (ret != 1)
+               return -EIO;

This needs to check ret != 2

+
+       isl6421->is_off = is_off;
+
+       /* On overflow, the device will try again after 900 ms (typically) */
+       if (isl6421->is_off && (buf & ISL6421_OLF1))
+               msleep(1000);
+
+       if (isl6421->is_off && !is_off) {
+               isl6421->config &= ~ISL6421_EN1;
+
+               ret = i2c_transfer(isl6421->i2c, msg, 2);
+               if (ret < 0)
+                       return ret;
+               if (ret != 1)
+                       return -EIO;
+       }

Same again

+
+       /* Check if overload flag is active. If so, disable power */
+       if (buf & ISL6421_OLF1) {
+               isl6421->config &= ~(ISL6421_VSEL1 | ISL6421_EN1);
+               ret = i2c_transfer(isl6421->i2c, msg, 1);
+               if (ret < 0)
+                       return ret;
+               if (ret != 1)
+                       return -EIO;
+               isl6421->is_off = true;
+
+               dev_warn(&isl6421->i2c->dev,
+                        "Overload current detected. disabling LNBf power\n");
+               return -EINVAL;
+       }
+       return 0;
  }
static int isl6421_enable_high_lnb_voltage(struct dvb_frontend *fe, long arg)
@@ -148,6 +210,8 @@ struct dvb_frontend *isl6421_attach(struct dvb_frontend 
*fe, struct i2c_adapter
                return NULL;
        }
+ isl6421->is_off = true;
+
        /* install release callback */
        fe->ops.release_sec = isl6421_release;


Once I changed these it worked fine - I can still tune in with this patch even switching from H to V. I've no idea if this fixes the bug logged in kaffeine though as I haven't seen it.


Jemma.

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