Hi Luiz,
On Fri, 2017-11-24 at 17:10 +0200, Luiz Augusto von Dentz wrote:
> Hi Steve,
>
> On Fri, Nov 24, 2017 at 4:39 PM, Steve Brown <sbrown@xxxxxxxxxxxx>
> wrote:
> > If the first command output in a new connection exceeds 20 bytes,
> > mesh_gatt_write sets the SAR to FIRST as the write_mtu is initially
> > 0
> > and the default is GATT_MTU-3 (20).
> >
> > When pipe_write gets called, a new larger write_mtu has been set,
> > but
> > the SAR is still set to FIRST. It's assumed that data->gatt_len >
> > max_len. However, it's not which causes lots of bogus output.
> >
> > I've added code to reset the SAR and length in acquire_write_reply
> > in
> > case write_mtu might have changed.
> >
> > This seems to work, but I'm sure there is a better way.
> >
> > Steve
> >
> > ---
> >
> >
> > diff --git a/mesh/gatt.c b/mesh/gatt.c
> > index 001eb17a8..3f59268f2 100644
> > --- a/mesh/gatt.c
> > +++ b/mesh/gatt.c
> > @@ -358,6 +362,7 @@ static void acquire_write_reply(DBusMessage
> > *message, void *user_data)
> > struct write_data *data = user_data;
> > DBusError error;
> > int fd;
> > + uint8_t max_len;
> >
> > dbus_error_init(&error);
> >
> > @@ -383,6 +388,18 @@ static void acquire_write_reply(DBusMessage
> > *message, void *user_data)
> >
> > write_io = pipe_io_new(fd);
> >
> > + /* Reset type and length as write_mtu may have changed */
> > + max_len = write_mtu ? write_mtu - 3 : GATT_MTU - 3;
> > + data->gatt_data[0] &= GATT_TYPE_MASK;
>
> Ive never really liked the idea of putting the SAR byte into data but
> it was required due to use of WriteValue, now perhaps we can even
> remove that since AcquireWrite is stable the sar byte can be set in
> an
> independent variable in pipe_write so we can move this logic there.
>
> > + if (max_len < data->gatt_len) {
> > + data->iov.iov_len = max_len;
> > + data->gatt_data[0] |= GATT_SAR_FIRST;
> > + }
> > +
> > + else
> > + data->iov.iov_len = data->gatt_len;
> > +
> > pipe_write(write_io, data);
> > }
> >
Thanks for your quick response.
I've just started reading the gatt-api doc. I might be ready to have at
this sometime in the spring.
I discovered the problem while trying to configure the new zephyr
mesh_shell. It should probably be fixed sooner than later. I best defer
to somebody more experienced.
Steve
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