On Mon, 19 May 2025, Imre Deak <[email protected]> wrote: > Due to a problem in the iTBT DP-in adapter's firmware the sink on a TBT > link may get disconnected inadvertently if the SINK_COUNT_ESI and the > DP_LINK_SERVICE_IRQ_VECTOR_ESI0 registers are read in a single AUX > transaction. Work around the issue by reading these registers in > separate transactions. > > The issue affects MTL+ platforms and will be fixed in the DP-in adapter > firmware, however releasing that firmware fix may take some time and is > not guaranteed to be available for all systems. Based on this apply the > workaround on affected platforms. > > See HSD #13013007775. > > v2: Cc'ing Mika Westerberg.
In general, please don't resend just for the sake of adding a Cc. It triggers a full CI rerun. BR, Jani. > > Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/13760 > Closes: https://gitlab.freedesktop.org/drm/i915/kernel/-/issues/14147 > Cc: Mika Westerberg <[email protected]> > Cc: [email protected] > Signed-off-by: Imre Deak <[email protected]> > --- > drivers/gpu/drm/i915/display/intel_dp.c | 17 +++++++++++++++++ > 1 file changed, 17 insertions(+) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c > b/drivers/gpu/drm/i915/display/intel_dp.c > index 21297bc4cc00d..208a953b04a2f 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -4538,6 +4538,23 @@ intel_dp_mst_disconnect(struct intel_dp *intel_dp) > static bool > intel_dp_get_sink_irq_esi(struct intel_dp *intel_dp, u8 *esi) > { > + struct intel_display *display = to_intel_display(intel_dp); > + > + /* > + * Display WA for HSD #13013007775: mtl/arl/lnl > + * Read the sink count and link service IRQ registers in separate > + * transactions to prevent disconnecting the sink on a TBT link > + * inadvertently. > + */ > + if (IS_DISPLAY_VER(display, 14, 20) && !display->platform.battlemage) { > + if (drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT_ESI, esi, 3) > != 3) > + return false; > + > + /* DP_SINK_COUNT_ESI + 3 == DP_LINK_SERVICE_IRQ_VECTOR_ESI0 */ > + return drm_dp_dpcd_readb(&intel_dp->aux, > DP_LINK_SERVICE_IRQ_VECTOR_ESI0, > + &esi[3]) == 1; > + } > + > return drm_dp_dpcd_read(&intel_dp->aux, DP_SINK_COUNT_ESI, esi, 4) == 4; > } -- Jani Nikula, Intel
