On Mon, May 19, 2025 at 04:53:08PM +0300, Jani Nikula wrote: > On Mon, 19 May 2025, Imre Deak <imre.d...@intel.com> 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.
In this case I wanted that as well. > 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 <mika.westerb...@linux.intel.com> > > Cc: sta...@vger.kernel.org > > Signed-off-by: Imre Deak <imre.d...@intel.com> > > --- > > 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
