> -----Original Message-----
> From: Dmitry Baryshkov <dmitry.baryshkov@xxxxxxxxxx>
> Sent: Friday, January 17, 2025 11:50 AM
> To: Kandpal, Suraj <suraj.kandpal@xxxxxxxxx>
> Cc: intel-xe@xxxxxxxxxxxxxxxxxxxxx; intel-gfx@xxxxxxxxxxxxxxxxxxxxx; dri-
> devel@xxxxxxxxxxxxxxxxxxxxx; Murthy, Arun R <arun.r.murthy@xxxxxxxxx>
> Subject: Re: [PATCH 2/2] drm/i915/lttpr: Enable Extended Wake Timeout
>
> On Fri, Jan 17, 2025 at 11:18:50AM +0530, Suraj Kandpal wrote:
> > Usually retimers take around 30 to 40ms to exit all devices from sleep
> > state. Extended wake timeout request helps to give additional time by
> > reading the DPCD register through which sink requests the minimal
> > amount of time required to wake the sink up.
> > Source device shall keep retying the AUX tansaction till the
> > extended timeout that is being granted for LTTPRs from the sink device
> >
> > --v2
> > -Grant the requested time only if greater than 1ms [Arun] -Reframe
> > commit message [Arun]
> >
> > Spec: DP v2.1 Section 3.6.12.3
> > Signed-off-by: Suraj Kandpal <suraj.kandpal@xxxxxxxxx>
> > ---
> > drivers/gpu/drm/i915/display/intel_ddi.c | 2 +
> > .../drm/i915/display/intel_dp_link_training.c | 49
> > +++++++++++++++++++ .../drm/i915/display/intel_dp_link_training.h |
> > 1 +
> > 3 files changed, 52 insertions(+)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_ddi.c
> > b/drivers/gpu/drm/i915/display/intel_ddi.c
> > index acb986bc1f33..96cabe618678 100644
> > --- a/drivers/gpu/drm/i915/display/intel_ddi.c
> > +++ b/drivers/gpu/drm/i915/display/intel_ddi.c
> > @@ -2645,6 +2645,8 @@ static void mtl_ddi_pre_enable_dp(struct
> intel_atomic_state *state,
> > if (!is_mst)
> > intel_dp_set_power(intel_dp, DP_SET_POWER_D0);
> >
> > + intel_dp_lttpr_wake_timeout_setup(intel_dp);
> > +
> > intel_dp_configure_protocol_converter(intel_dp, crtc_state);
> > if (!is_mst)
> > intel_dp_sink_enable_decompression(state,
> > diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > index 8b1977cfec50..c113b0be259e 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c
> > @@ -135,6 +135,55 @@ static bool
> intel_dp_lttpr_transparent_mode_enabled(struct intel_dp *intel_dp)
> > DP_PHY_REPEATER_MODE_TRANSPARENT;
> > }
> >
> > +void intel_dp_lttpr_wake_timeout_setup(struct intel_dp *intel_dp)
>
> Please move this function to drivers/gpu/drm/display/drm_dp_helper.c
> Except for the intel_dp_lttpr_transparent_mode_enabled() call there is
> nothing Intel-specific there.
>
Sure will do.
Regards,
Suraj Kandpal
> > +{
> > + struct intel_display *display = to_intel_display(intel_dp);
> > + u8 val = 1;
> > + int ret;
> > +
> > + if (intel_dp_lttpr_transparent_mode_enabled(intel_dp)) {
> > + static const u8 timeout_mapping[] = {
> > + [DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_1_MS] =
> 1,
> > + [DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_20_MS]
> = 20,
> > + [DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_40_MS]
> = 40,
> > + [DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_20_MS]
> = 20,
> > + [DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_80_MS]
> = 80,
> > + [DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_100_MS]
> = 100,
> > + };
> > +
> > + ret = drm_dp_dpcd_readb(&intel_dp->aux,
> > +
> DP_EXTENDED_DPRX_SLEEP_WAKE_TIMEOUT_REQUEST, &val);
> > + if (ret != 1) {
> > + drm_dbg_kms(display->drm,
> > + "Failed to read Extended sleep wake
> timeout request\n");
> > + return;
> > + }
> > +
> > + val = (val < sizeof(timeout_mapping) &&
> timeout_mapping[val]) ?
> > + timeout_mapping[val] : 1;
> > +
> > + if (val > 1)
> > + drm_dp_dpcd_writeb(&intel_dp->aux,
> > +
> DP_EXTENDED_DPRX_SLEEP_WAKE_TIMEOUT_GRANT,
> > +
> DP_DPRX_SLEEP_WAKE_TIMEOUT_PERIOD_GRANTED);
> > + } else {
> > + ret = drm_dp_dpcd_readb(&intel_dp->aux,
> > +
> DP_PHY_REPEATER_EXTENDED_WAIT_TIMEOUT, &val);
> > + if (ret != 1) {
> > + drm_dbg_kms(display->drm,
> > + "Failed to read Extended sleep wake
> timeout request\n");
> > + return;
> > + }
> > +
> > + val = (val &
> DP_EXTENDED_WAKE_TIMEOUT_REQUEST_MASK) ?
> > + (val &
> DP_EXTENDED_WAKE_TIMEOUT_REQUEST_MASK) * 10 : 1;
> > +
> > + if (val > 1)
> > + drm_dp_dpcd_writeb(&intel_dp->aux,
> DP_PHY_REPEATER_EXTENDED_WAIT_TIMEOUT,
> > +
> DP_EXTENDED_WAKE_TIMEOUT_GRANT);
> > + }
> > +}
> > +
> > /*
> > * Read the LTTPR common capabilities and switch the LTTPR PHYs to
> > * non-transparent mode if this is supported. Preserve the diff --git
> > a/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> > b/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> > index 2066b9146762..cd4e0d6db6ed 100644
> > --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> > +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.h
> > @@ -15,6 +15,7 @@ struct intel_dp;
> >
> > int intel_dp_read_dprx_caps(struct intel_dp *intel_dp, u8
> > dpcd[DP_RECEIVER_CAP_SIZE]); int
> > intel_dp_init_lttpr_and_dprx_caps(struct intel_dp *intel_dp);
> > +void intel_dp_lttpr_wake_timeout_setup(struct intel_dp *intel_dp);
> >
> > void intel_dp_link_training_set_mode(struct intel_dp *intel_dp,
> > int link_rate, bool is_vrr);
> > --
> > 2.34.1
> >
>
> --
> With best wishes
> Dmitry
