On Tue, 2022-02-15 at 15:47 +0200, Lisovskiy, Stanislav wrote:
> On Thu, Feb 10, 2022 at 10:52:23AM -0800, José Roberto de Souza wrote:
> > PSR2 workaround required when mode has delayed vblank.
> >
> > BSpec: 52890
> > BSpec: 49421
> > Cc: Jouni Högander <jouni.hogander@xxxxxxxxx>
> > Signed-off-by: José Roberto de Souza <jose.souza@xxxxxxxxx>
>
>
> I think we better implement it in a more generic way.
> BSpec 71580 formulates this workaround more precisely:
>
> "
> If any low power watermark is disabled because the package C state
> has too much latency for the size of Vblank and PSR1 or PSR2 is enabled,
> set the register bit for this pipe (listing below) to 1 to disable a
> PSR optimization to override to the maximum watermark.
> Clear the bit if the size of Vblank does not require low power watermarks to be disabled
> or PSR* is disabled."
This is a different workaround than the one implemented in this patch.
The programming bits are the same but they have different "triggers" checks.
>
>
> Pipe A 0x46430 bit 23
>
> Pipe B 0x46430 bit 24
>
> Pipe C 0x46430 bit 25
>
> Pipe D 0x46430 bit 31
>
>
> TRANS_SET_CONTEXT_LATENCY is used to delay the vblank"
>
>
> Almost we must ensure that one:
>
> Vblank time >= MAX(framestart delay + package C state latency + watermark 0 time + pipe scaler pre-fill time + DSC pre-fill time,
> PSR2 vblank time, SDP vblank time)
>
> Line time >= PSR2 line time
>
> I'm currently working on the latter one. I have suggestion that one I finish
> with calculations required for this formula, I can provide some api for this
> patch in order to check if PSR can be enabled and workaround has to be applied.
>
> Stan
>
>
> > ---
> > drivers/gpu/drm/i915/display/intel_psr.c | 40 ++++++++++++++++++++++--
> > drivers/gpu/drm/i915/i915_reg.h | 13 +++++---
> > 2 files changed, 46 insertions(+), 7 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/display/intel_psr.c b/drivers/gpu/drm/i915/display/intel_psr.c
> > index 72bd8d3261e0c..2e0b092f4b6be 100644
> > --- a/drivers/gpu/drm/i915/display/intel_psr.c
> > +++ b/drivers/gpu/drm/i915/display/intel_psr.c
> > @@ -1063,7 +1063,23 @@ static void intel_psr_activate(struct intel_dp *intel_dp)
> > intel_dp->psr.active = true;
> > }
> >
> > -static void intel_psr_enable_source(struct intel_dp *intel_dp)
> > +static u32 wa_16013835468_bit_get(struct intel_dp *intel_dp)
> > +{
> > + switch (intel_dp->psr.pipe) {
> > + case PIPE_A:
> > + return LATENCY_REPORTING_REMOVED_PIPE_A;
> > + case PIPE_B:
> > + return LATENCY_REPORTING_REMOVED_PIPE_B;
> > + case PIPE_C:
> > + return LATENCY_REPORTING_REMOVED_PIPE_C;
> > + default:
> > + MISSING_CASE(intel_dp->psr.pipe);
> > + return 0;
> > + }
> > +}
> > +
> > +static void intel_psr_enable_source(struct intel_dp *intel_dp,
> > + const struct intel_crtc_state *crtc_state)
> > {
> > struct drm_i915_private *dev_priv = dp_to_i915(intel_dp);
> > enum transcoder cpu_transcoder = intel_dp->psr.transcoder;
> > @@ -1133,6 +1149,20 @@ static void intel_psr_enable_source(struct intel_dp *intel_dp)
> > if (IS_ALDERLAKE_P(dev_priv))
> > intel_de_rmw(dev_priv, CLKGATE_DIS_MISC, 0,
> > CLKGATE_DIS_MISC_DMASC_GATING_DIS);
> > +
> > + /* Wa_16013835468:tgl[b0+], dg1 */
> > + if (IS_TGL_DISPLAY_STEP(dev_priv, STEP_B0, STEP_FOREVER) ||
> > + IS_DG1(dev_priv)) {
> > + u16 vtotal, vblank;
> > +
> > + vtotal = crtc_state->uapi.adjusted_mode.crtc_vtotal -
> > + crtc_state->uapi.adjusted_mode.crtc_vdisplay;
> > + vblank = crtc_state->uapi.adjusted_mode.crtc_vblank_end -
> > + crtc_state->uapi.adjusted_mode.crtc_vblank_start;
> > + if (vblank > vtotal)
> > + intel_de_rmw(dev_priv, GEN8_CHICKEN_DCPR_1, 0,
> > + wa_16013835468_bit_get(intel_dp));
> > + }
> > }
> > }
> >
> > @@ -1198,7 +1228,7 @@ static void intel_psr_enable_locked(struct intel_dp *intel_dp,
> > intel_write_dp_vsc_sdp(encoder, crtc_state, &crtc_state->psr_vsc);
> > intel_snps_phy_update_psr_power_state(dev_priv, phy, true);
> > intel_psr_enable_sink(intel_dp);
> > - intel_psr_enable_source(intel_dp);
> > + intel_psr_enable_source(intel_dp, crtc_state);
> > intel_dp->psr.enabled = true;
> > intel_dp->psr.paused = false;
> >
> > @@ -1297,6 +1327,12 @@ static void intel_psr_disable_locked(struct intel_dp *intel_dp)
> > if (IS_ALDERLAKE_P(dev_priv))
> > intel_de_rmw(dev_priv, CLKGATE_DIS_MISC,
> > CLKGATE_DIS_MISC_DMASC_GATING_DIS, 0);
> > +
> > + /* Wa_16013835468:tgl[b0+], dg1 */
> > + if (IS_TGL_DISPLAY_STEP(dev_priv, STEP_B0, STEP_FOREVER) ||
> > + IS_DG1(dev_priv))
> > + intel_de_rmw(dev_priv, GEN8_CHICKEN_DCPR_1,
> > + wa_16013835468_bit_get(intel_dp), 0);
> > }
> >
> > intel_snps_phy_update_psr_power_state(dev_priv, phy, false);
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index 87c92314ee269..1cd4056400b63 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -6040,11 +6040,14 @@
> > #define HSW_NDE_RSTWRN_OPT _MMIO(0x46408)
> > #define RESET_PCH_HANDSHAKE_ENABLE (1 << 4)
> >
> > -#define GEN8_CHICKEN_DCPR_1 _MMIO(0x46430)
> > -#define SKL_SELECT_ALTERNATE_DC_EXIT REG_BIT(30)
> > -#define ICL_DELAY_PMRSP REG_BIT(22)
> > -#define DISABLE_FLR_SRC REG_BIT(15)
> > -#define MASK_WAKEMEM REG_BIT(13)
> > +#define GEN8_CHICKEN_DCPR_1 _MMIO(0x46430)
> > +#define SKL_SELECT_ALTERNATE_DC_EXIT REG_BIT(30)
> > +#define LATENCY_REPORTING_REMOVED_PIPE_C REG_BIT(25)
> > +#define LATENCY_REPORTING_REMOVED_PIPE_B REG_BIT(24)
> > +#define LATENCY_REPORTING_REMOVED_PIPE_A REG_BIT(23)
> > +#define ICL_DELAY_PMRSP REG_BIT(22)
> > +#define DISABLE_FLR_SRC REG_BIT(15)
> > +#define MASK_WAKEMEM REG_BIT(13)
> >
> > #define GEN11_CHICKEN_DCPR_2 _MMIO(0x46434)
> > #define DCPR_MASK_MAXLATENCY_MEMUP_CLR REG_BIT(27)
> > --
> > 2.35.1
> >
