On Fri, May 24, 2019 at 08:35:32PM +0300, Imre Deak wrote: > Atm AUX-B transfers can fail with the following error if AUX-A is not > enabled: > > [ 594.594108] [drm:intel_dp_aux_xfer [i915]] dp_aux_ch timeout status 0x7c2003ff > [ 594.615854] [drm:intel_dp_aux_xfer [i915]] *ERROR* dp aux hw did not signal timeout! > [ 594.632851] [drm:intel_dp_aux_xfer [i915]] *ERROR* dp aux hw did not signal timeout! > [ 594.632915] [drm:intel_dp_aux_xfer [i915]] *ERROR* dp_aux_ch not done status 0xac2003ff > [ 594.641786] ------------[ cut here ]------------ > [ 594.641790] dp_aux_ch not started status 0xac2003ff > [ 594.641874] WARNING: CPU: 4 PID: 1366 at drivers/gpu/drm/i915/intel_dp.c:1268 intel_dp_aux_xfer+0x232/0x890 [i915] > > Ville noticed this issue already earlier and managed to work around it > by keeping AUX-A always powered whenever AUX-B was used. He also > reported the issue to HW folks and they have now root caused the problem > and updated BSpec with a fix (see internal BSpec/Index/21257, > HSD/1607152412). > > I noticed the same error - even with the WA being applied - while doing > AUX transfers with Chamelium being connected with a DP cable to the > source but letting Chamelium imitate an unplug. This is probably some > unstandard way on Chamelium's behalf of disconnecting itself from the > AUX pins. For instance it could still pull on the AUX pins which would > prevent the source from detecting AUX timeouts in the proper way, > leading to the ERRORs or WARNs seen in the logs in the Reference: bug > below. > > In case I disconnect the sink properly (the cable itself, not via the > Chamelium unplug xmlrpc command) then the AUX timeout signaling works > properly and so there won't be any ERRORs/WARNs emitted. > > Reference: https://bugs.freedesktop.org/show_bug.cgi?id=110718 > Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Reported-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> Reviewed-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx> > --- > drivers/gpu/drm/i915/i915_reg.h | 3 +++ > drivers/gpu/drm/i915/intel_combo_phy.c | 6 ++++++ > 2 files changed, 9 insertions(+) > > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h > index 87e8780711d7..bae4a2547eb2 100644 > --- a/drivers/gpu/drm/i915/i915_reg.h > +++ b/drivers/gpu/drm/i915/i915_reg.h > @@ -1846,6 +1846,9 @@ enum i915_power_well_id { > #define VOLTAGE_INFO_MASK (3 << 24) > #define VOLTAGE_INFO_SHIFT 24 > > +#define ICL_PORT_COMP_DW8(port) _MMIO(_ICL_PORT_COMP_DW(8, port)) > +#define IREFGEN (1 << 24) > + > #define CNL_PORT_COMP_DW9 _MMIO(0x162124) > #define ICL_PORT_COMP_DW9(port) _MMIO(_ICL_PORT_COMP_DW(9, port)) > > diff --git a/drivers/gpu/drm/i915/intel_combo_phy.c b/drivers/gpu/drm/i915/intel_combo_phy.c > index 19a9333b727a..98213cc58736 100644 > --- a/drivers/gpu/drm/i915/intel_combo_phy.c > +++ b/drivers/gpu/drm/i915/intel_combo_phy.c > @@ -275,6 +275,12 @@ static void icl_combo_phys_init(struct drm_i915_private *dev_priv) > > cnl_set_procmon_ref_values(dev_priv, port); > > + if (port == PORT_A) { > + val = I915_READ(ICL_PORT_COMP_DW8(port)); > + val |= IREFGEN; > + I915_WRITE(ICL_PORT_COMP_DW8(port), val); > + } > + > val = I915_READ(ICL_PORT_COMP_DW0(port)); > val |= COMP_INIT; > I915_WRITE(ICL_PORT_COMP_DW0(port), val); > -- > 2.17.1 -- Ville Syrjälä Intel _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
