> -----Original Message-----
> From: Hogander, Jouni <jouni.hogander@xxxxxxxxx>
> Sent: Monday, November 6, 2023 10:41 AM
> To: Kahola, Mika <mika.kahola@xxxxxxxxx>; intel-gfx@xxxxxxxxxxxxxxxxxxxxx
> Cc: ville.syrjala@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH v3] drm/i915/display: Support PSR entry VSC packet to be transmitted one frame earlier
>
> On Fri, 2023-11-03 at 11:32 +0200, Mika Kahola wrote:
> > Display driver shall read DPCD 00071h[3:1] during configuration to get
> > PSR setup time. This register provides the setup time requirement on
> > the VSC SDP entry packet. If setup time cannot be met with the current
> > timings (e.g., PSR setup time + other blanking requirements > blanking
> > time), driver should enable sending VSC SDP one frame earlier before
> > sending the capture frame.
> >
> > BSpec: 69895 (PSR Entry Setup Frames 17:16)
> >
> > v2: Write frames before su entry to correct register (Ville, Jouni)
> > Move frames before su entry calculation to it's
> > own function (Ville, Jouni)
> > Rename PSR Entry Setup Frames register to indicate
> > Lunarlake specificity (Jouni)
> > v3: Modify setup entry frames calculation function to
> > return the actual frames (Ville)
> > Match comment with actual implementation (Jouni)
> >
> > Signed-off-by: Mika Kahola <mika.kahola@xxxxxxxxx>
> > ---
> > .../drm/i915/display/intel_display_types.h | 1 +
> > drivers/gpu/drm/i915/display/intel_psr.c | 82 +++++++++++++++--
> > --
> > drivers/gpu/drm/i915/display/intel_psr_regs.h | 2 +
> > 3 files changed, 71 insertions(+), 14 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_display_types.h
> > b/drivers/gpu/drm/i915/display/intel_display_types.h
> > index 047fe3f8905a..92f06d67fd1e 100644
> > --- a/drivers/gpu/drm/i915/display/intel_display_types.h
> > +++ b/drivers/gpu/drm/i915/display/intel_display_types.h
> > @@ -1708,6 +1708,7 @@ struct intel_psr {
> > u32 dc3co_exitline;
> > u32 dc3co_exit_delay;
> > struct delayed_work dc3co_work;
> > + u8 entry_setup_frames;
> > };
> >
> > struct intel_dp {
> > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c
> > b/drivers/gpu/drm/i915/display/intel_psr.c
> > index ecd24a0b86cb..497e4c26f4a6 100644
> > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > @@ -592,6 +592,9 @@ static void intel_psr_enable_sink(struct intel_dp
> > *intel_dp)
> > if (intel_dp->psr.req_psr2_sdp_prior_scanline)
> > dpcd_val |= DP_PSR_SU_REGION_SCANLINE_CAPTURE;
> >
> > + if (intel_dp->psr.entry_setup_frames > 0)
> > + dpcd_val |= DP_PSR_FRAME_CAPTURE;
> > +
> > drm_dp_dpcd_writeb(&intel_dp->aux, DP_PSR_EN_CFG, dpcd_val);
> >
> > drm_dp_dpcd_writeb(&intel_dp->aux, DP_SET_POWER,
> > DP_SET_POWER_D0); @@ -690,6 +693,9 @@ static void
> > hsw_activate_psr1(struct intel_dp
> > *intel_dp)
> > if (DISPLAY_VER(dev_priv) >= 8)
> > val |= EDP_PSR_CRC_ENABLE;
> >
> > + if (DISPLAY_VER(dev_priv) >= 20)
> > + val |= LNL_EDP_PSR_ENTRY_SETUP_FRAMES(intel_dp-
> > >psr.entry_setup_frames);
> > +
> > intel_de_rmw(dev_priv, psr_ctl_reg(dev_priv, cpu_transcoder),
> > ~EDP_PSR_RESTORE_PSR_ACTIVE_CTX_MASK, val);
> > }
> > @@ -727,11 +733,27 @@ static int psr2_block_count(struct intel_dp
> > *intel_dp)
> > return psr2_block_count_lines(intel_dp) / 4;
> > }
> >
> > +static u8 get_frames_before_su_entry(struct intel_dp *intel_dp) {
> > + u8 frames_before_su_entry;
> > +
> > + frames_before_su_entry = max_t(u8,
> > + intel_dp-
> > >psr.sink_sync_latency + 1,
> > + 2);
> > +
> > + /* Entry setup frames must be at least 1 less than frames
> > before SU entry */
> > + if (intel_dp->psr.entry_setup_frames >=
> > frames_before_su_entry)
> > + frames_before_su_entry = intel_dp-
> > >psr.entry_setup_frames + 1;
> > +
> > + return frames_before_su_entry; }
> > +
> > static void hsw_activate_psr2(struct intel_dp *intel_dp)
> > {
> > struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> > enum transcoder cpu_transcoder = intel_dp->psr.transcoder;
> > u32 val = EDP_PSR2_ENABLE;
> > + u32 psr_val = 0;
> >
> > val |=
> > EDP_PSR2_IDLE_FRAMES(psr_compute_idle_frames(intel_dp));
> >
> > @@ -741,7 +763,8 @@ static void hsw_activate_psr2(struct intel_dp
> > *intel_dp)
> > if (DISPLAY_VER(dev_priv) >= 10 && DISPLAY_VER(dev_priv) <=
> > 12)
> > val |= EDP_Y_COORDINATE_ENABLE;
> >
> > - val |= EDP_PSR2_FRAME_BEFORE_SU(max_t(u8, intel_dp-
> > >psr.sink_sync_latency + 1, 2));
> > + val |=
> > EDP_PSR2_FRAME_BEFORE_SU(get_frames_before_su_entry(intel_dp));
> > +
> > val |= intel_psr2_get_tp_time(intel_dp);
> >
> > if (DISPLAY_VER(dev_priv) >= 12) { @@ -785,6 +808,9 @@ static
> > void hsw_activate_psr2(struct intel_dp
> > *intel_dp)
> > if (intel_dp->psr.req_psr2_sdp_prior_scanline)
> > val |= EDP_PSR2_SU_SDP_SCANLINE;
> >
> > + if (DISPLAY_VER(dev_priv) >= 20)
> > + psr_val |= LNL_EDP_PSR_ENTRY_SETUP_FRAMES(intel_dp-
> > >psr.entry_setup_frames);
> > +
> > if (intel_dp->psr.psr2_sel_fetch_enabled) {
> > u32 tmp;
> >
> > @@ -798,7 +824,7 @@ static void hsw_activate_psr2(struct intel_dp
> > *intel_dp)
> > * PSR2 HW is incorrectly using EDP_PSR_TP1_TP3_SEL and BSpec
> > is
> > * recommending keep this bit unset while PSR2 is enabled.
> > */
> > - intel_de_write(dev_priv, psr_ctl_reg(dev_priv,
> > cpu_transcoder), 0);
> > + intel_de_write(dev_priv, psr_ctl_reg(dev_priv,
> > cpu_transcoder), psr_val);
> >
> > intel_de_write(dev_priv, EDP_PSR2_CTL(cpu_transcoder), val);
> > }
> > @@ -1066,6 +1092,40 @@ static bool _compute_psr2_wake_times(struct
> > intel_dp *intel_dp,
> > return true;
> > }
> >
> > +static u8 intel_psr_set_entry_setup_frames(struct intel_dp
> > *intel_dp,
> > + const struct
> > drm_display_mode *adjusted_mode)
>
> I think "set" is not correct here. intel_psr_get_entry_setup_frames is more appropriate.
I was thinking that this we would set the register value with this value but since we do not set the actual register here, the naming is not the best possible. I will switch to use "get" instead of "set".
>
> > +{
> > + struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
>
> You should use name i915 here.
Yes, we should use i915 nowadays.
>
> > + int psr_setup_time = drm_dp_psr_setup_time(intel_dp-
> > >psr_dpcd);
> > + u8 entry_setup_frames = 0;
> > +
> > + if (psr_setup_time < 0) {
> > + drm_dbg_kms(&dev_priv->drm,
> > + "PSR condition failed: Invalid PSR setup
> > time (0x%02x)\n",
> > + intel_dp->psr_dpcd[1]);
> > + return -ETIME;
> > + }
> > +
> > +
> > + if (intel_usecs_to_scanlines(adjusted_mode, psr_setup_time) >
> > + adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vdisplay
> > - 1) {
> > + if (DISPLAY_VER(dev_priv) >= 20) {
> > + /* setup entry frames can be set up to 3
> > frames */
> > + entry_setup_frames = 1;
> > + drm_dbg_kms(&dev_priv->drm,
> > + "PSR setup entry frames set to
> > %d\n",
> > + entry_setup_frames);
>
> Don't refer "setting" here as this is just returning the value. Not setting it.
Yes, just like previously I was thinking setting the register value but I will drop the "set" out here.
Thanks for the review and comments!
-Mika-
>
> BR,
>
> Jouni Högander
>
> > + } else {
> > + drm_dbg_kms(&dev_priv->drm,
> > + "PSR condition failed: PSR setup
> > time (%d us) too long\n",
> > + psr_setup_time);
> > + return -ETIME;
> > + }
> > + }
> > +
> > + return entry_setup_frames;
> > +}
> > +
> > static bool intel_psr2_config_valid(struct intel_dp *intel_dp,
> > struct intel_crtc_state
> > *crtc_state)
> > {
> > @@ -1213,7 +1273,7 @@ void intel_psr_compute_config(struct intel_dp
> > *intel_dp,
> > struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> > const struct drm_display_mode *adjusted_mode =
> > &crtc_state->hw.adjusted_mode;
> > - int psr_setup_time;
> > + u8 entry_setup_frames;
> >
> > /*
> > * Current PSR panels don't work reliably with VRR enabled @@
> > -1242,19 +1302,13 @@ void intel_psr_compute_config(struct intel_dp
> > *intel_dp,
> > return;
> > }
> >
> > - psr_setup_time = drm_dp_psr_setup_time(intel_dp->psr_dpcd);
> > - if (psr_setup_time < 0) {
> > - drm_dbg_kms(&dev_priv->drm,
> > - "PSR condition failed: Invalid PSR setup
> > time (0x%02x)\n",
> > - intel_dp->psr_dpcd[1]);
> > - return;
> > - }
> > + entry_setup_frames =
> > intel_psr_set_entry_setup_frames(intel_dp, adjusted_mode);
> >
> > - if (intel_usecs_to_scanlines(adjusted_mode, psr_setup_time) >
> > - adjusted_mode->crtc_vtotal - adjusted_mode->crtc_vdisplay
> > - 1) {
> > + if (entry_setup_frames >= 0) {
> > + intel_dp->psr.entry_setup_frames =
> > entry_setup_frames;
> > + } else {
> > drm_dbg_kms(&dev_priv->drm,
> > - "PSR condition failed: PSR setup time (%d
> > us) too long\n",
> > - psr_setup_time);
> > + "PSR condition failed: PSR setup timing
> > not met\n");
> > return;
> > }
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_psr_regs.h
> > b/drivers/gpu/drm/i915/display/intel_psr_regs.h
> > index d39951383c92..efe4306b37e0 100644
> > --- a/drivers/gpu/drm/i915/display/intel_psr_regs.h
> > +++ b/drivers/gpu/drm/i915/display/intel_psr_regs.h
> > @@ -35,6 +35,8 @@
> > #define
> > EDP_PSR_MIN_LINK_ENTRY_TIME_0_LINES REG_FIELD_PREP(EDP_PSR_MIN_LINK_
> > ENTRY_TIME_MASK, 3)
> > #define EDP_PSR_MAX_SLEEP_TIME_MASK REG_GENMASK(24, 20)
> > #define
> > EDP_PSR_MAX_SLEEP_TIME(x) REG_FIELD_PREP(EDP_PSR_MAX_SLEEP
> > _TIME_MASK, (x))
> > +#define LNL_EDP_PSR_ENTRY_SETUP_FRAMES_MASK REG_GENMASK(17, 16)
> > +#define
> > LNL_EDP_PSR_ENTRY_SETUP_FRAMES(x) REG_FIELD_PREP(LNL_EDP_PSR_ENTRY
> > _SETUP_FRAMES_MASK, (x))
> > #define EDP_PSR_SKIP_AUX_EXIT REG_BIT(12)
> > #define EDP_PSR_TP_MASK REG_BIT(11)
> > #define
> > EDP_PSR_TP_TP1_TP2 REG_FIELD_PREP(EDP_PSR_TP_MASK,
> > 0)
