On Sun, May 01, 2022 at 11:33:21PM +0300, Gil Fine wrote: > Here we configure TMU mode to Hifi-Uni once DP tunnel is created. DisplayPort (at least use that in the $subject). > This is due to accuracy requirement for DP tunneling as appears in > CM guide 1.0, section 7.3.2 > Due to Intel HW limitation, once we changed the TMU mode to Hifi-Uni HW -> hardware HiFi uni-directional > (when DP is tunnel exists), we don't change TMU mode back to Normal-Uni, normal un-idirectional > even if DP tunnel is teared-down later. torn down > > Signed-off-by: Gil Fine <gil.fine@xxxxxxxxx> > --- > drivers/thunderbolt/tb.c | 40 ++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 40 insertions(+) > > diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c > index 05a084e3e9f6..efe53d221ca8 100644 > --- a/drivers/thunderbolt/tb.c > +++ b/drivers/thunderbolt/tb.c > @@ -50,6 +50,8 @@ struct tb_hotplug_event { > }; > > static void tb_handle_hotplug(struct work_struct *work); > +static int tb_enable_tmu_1st_child(struct tb *tb, > + enum tb_switch_tmu_rate rate); > > static void tb_queue_hotplug(struct tb *tb, u64 route, u8 port, bool unplug) > { > @@ -118,6 +120,13 @@ static void tb_switch_discover_tunnels(struct tb_switch *sw, > switch (port->config.type) { > case TB_TYPE_DP_HDMI_IN: > tunnel = tb_tunnel_discover_dp(tb, port, alloc_hopids); > + /* > + * In case of DP tunnel exists, change TMU mode to > + * HiFi for CL0s to work. > + */ > + if (tunnel) > + tb_enable_tmu_1st_child(tb, > + TB_SWITCH_TMU_RATE_HIFI); > break; > > case TB_TYPE_PCIE_DOWN: > @@ -235,6 +244,31 @@ static int tb_enable_tmu(struct tb_switch *sw) > return tb_switch_tmu_enable(sw); > } > > +/* > + * Once a DP tunnel exists in the domain, we set the TMU mode so that > + * it meets the accuracy requirements and also enables CLx entry (CL0s). > + * We set the TMU mode of the first depth router(s) for CL0s to work. > + */ > +static int tb_enable_tmu_1st_child(struct tb *tb, enum tb_switch_tmu_rate rate) > +{ > + struct tb_switch *root_sw = tb->root_switch; > + struct tb_port *port; > + > + tb_switch_for_each_port(root_sw, port) { Can't you use device_for_each_child() here? > + struct tb_switch *sw; > + int ret; > + > + if (!tb_port_has_remote(port) || !tb_port_is_null(port)) > + continue; > + sw = port->remote->sw; > + tb_switch_tmu_configure(sw, rate, tb_switch_is_clx_enabled(sw)); > + if (tb_switch_tmu_enable(sw)) > + tb_dbg(tb, "Fail switching TMU to HiFi for 1st depth router %d\n", ret); > + } > + > + return 0; > +} > + > /** > * tb_find_unused_port() - return the first inactive port on @sw > * @sw: Switch to find the port on > @@ -981,6 +1015,12 @@ static void tb_tunnel_dp(struct tb *tb) > > list_add_tail(&tunnel->list, &tcm->tunnel_list); > tb_reclaim_usb3_bandwidth(tb, in, out); > + /* > + * In case of DP tunnel exists, change TMU mode to > + * HiFi for CL0s to work. > + */ > + tb_enable_tmu_1st_child(tb, TB_SWITCH_TMU_RATE_HIFI); > + > return; > > err_free: > -- > 2.17.1