[lvc-project] [PATCH BlueZ 1/2] audio: actually try to enable MTU auto-tuning

[Fedor Pchelkin]

On Tue, 28. Jan 16:59, Luiz Augusto von Dentz wrote:
> > @@ -622,7 +623,7 @@ static gboolean set_l2opts(int sock, uint16_t imtu, uint16_t omtu,
> >                 return FALSE;
> >         }
> >
> > -       if (imtu)
> > +       if (imtu || auto_mtu)
> >                 l2o.imtu = imtu;
> 
> We might need to do some more special handling for auto_mtu, so in
> case it fail we retry with the default values instead.

Yep, a good point. And I see now it _might_ fail here for the kernels
without the corresponding patch.

> >  static gboolean l2cap_set(int sock, uint8_t src_type, int sec_level,
> > -                               uint16_t imtu, uint16_t omtu, uint8_t mode,
> > -                               int central, int flushable, uint32_t priority,
> > -                               GError **err)
> > +                               uint16_t imtu, uint16_t omtu, uint8_t auto_mtu,
> > +                               uint8_t mode, int central, int flushable,
> > +                               uint32_t priority, GError **err)
> >  {
> > -       if (imtu || omtu || mode) {
> > +       if (imtu || omtu || auto_mtu || mode) {
> >                 gboolean ret = FALSE;
> >
> >                 if (src_type == BDADDR_BREDR)
> > -                       ret = set_l2opts(sock, imtu, omtu, mode, err);
> > +                       ret = set_l2opts(sock, imtu, omtu, auto_mtu, mode, err);
> 
> Perhaps here we do:
> 
> if (ret && auto_mtu)
>   ret = set_l2opts(sock, imtu, omtu, false, mode, err);
> 
> Thoughts?

Agreed, trying the original default behavior will work with existing
kernels. I'll respin the series.

> 
> >                 else {
> > -                       if (imtu)
> > +                       if (imtu || auto_mtu)
> >                                 ret = set_le_imtu(sock, imtu, err);

Huh, the BT_RCVMTU case may also fail for L2CAP_MODE_EXT_FLOWCTL (that's
not something I'm prepared to reproduce though).

l2cap_chan_reconfigure() will reject a zero imtu. Worth adding some another
kernel patch or ECRED should not actually support MTU auto-tuning?