Re: [PATCH 3/6] drm/i915/lvds: Restore initial HW state during encoder enabling

Imre Deak
2016-08-09T14:40:35Z

On ti, 2016-08-09 at 15:48 +0300, Ville Syrjälä wrote:
> On Tue, Aug 09, 2016 at 02:34:09PM +0300, Imre Deak wrote:
> > Atm the LVDS encoder depends on the PPS HW context being saved/restored
> > from generic suspend/resume code. Since the PPS is specific to the LVDS
> > and eDP encoders a cleaner way is to reinitialize it during encoder
> > enabling, so do this here for LVDS. Follow-up patches will init the PPS
> > for the eDP encoder similarly and remove the suspend/resume time save /
> > restore.
> >
> > Signed-off-by: Imre Deak <imre.deak@intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_reg.h   |   1 +
> >  drivers/gpu/drm/i915/intel_lvds.c | 103 +++++++++++++++++++++++++++++++++-----
> >  2 files changed, 91 insertions(+), 13 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> > index 889508f..da82744 100644
> > --- a/drivers/gpu/drm/i915/i915_reg.h
> > +++ b/drivers/gpu/drm/i915/i915_reg.h
> > @@ -3710,6 +3710,7 @@ enum {
> >
> >  #define _PP_ON_DELAYS 0x61208
> >  #define PP_ON_DELAYS(pps_idx) _MMIO_PPS(pps_idx, _PP_ON_DELAYS)
> > +#define  PANEL_PORT_SELECT_SHIFT 30
> >  #define  PANEL_PORT_SELECT_MASK (3 << 30)
> >  #define  PANEL_PORT_SELECT_LVDS (0 << 30)
> >  #define  PANEL_PORT_SELECT_DPA (1 << 30)
> > diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
> > index c5739fc..d5158e5 100644
> > --- a/drivers/gpu/drm/i915/intel_lvds.c
> > +++ b/drivers/gpu/drm/i915/intel_lvds.c
> > @@ -48,6 +48,20 @@ struct intel_lvds_connector {
> >   struct notifier_block lid_notifier;
> >  };
> >
> > +struct intel_lvds_pps {
> > + /* 100us units */
> > + int t1_t2;
> > + int t3;
> > + int t4;
> > + int t5;
> > + int tx;
> > +
> > + int divider;
> > +
> > + int port;
> > + bool reset_on_powerdown;
> > +};
> > +
> >  struct intel_lvds_encoder {
> >   struct intel_encoder base;
> >
> > @@ -55,6 +69,9 @@ struct intel_lvds_encoder {
> >   i915_reg_t reg;
> >   u32 a3_power;
> >
> > + struct intel_lvds_pps init_pps;
> > + u32 init_lvds_val;
> > +
> >   struct intel_lvds_connector *attached_connector;
> >  };
> >
> > @@ -136,6 +153,72 @@ static void intel_lvds_get_config(struct intel_encoder *encoder,
> >   pipe_config->base.adjusted_mode.crtc_clock = pipe_config->port_clock;
> >  }
> >
> > +static void intel_lvds_pps_get_hw_state(struct drm_i915_private *dev_priv,
> > + struct intel_lvds_pps *pps)
> > +{
> > + u32 val;
> > +
> > + pps->reset_on_powerdown = I915_READ(PP_CONTROL(0)) & PANEL_POWER_RESET;
> > +
> > + val = I915_READ(PP_ON_DELAYS(0));
> > + pps->port = (val & PANEL_PORT_SELECT_MASK) >>
> > +     PANEL_PORT_SELECT_SHIFT;
> > + pps->t1_t2 = (val & PANEL_POWER_UP_DELAY_MASK) >>
> > +      PANEL_POWER_UP_DELAY_SHIFT;
> > + pps->t5 = (val & PANEL_LIGHT_ON_DELAY_MASK) >>
> > +   PANEL_LIGHT_ON_DELAY_SHIFT;
> > +
> > + val = I915_READ(PP_OFF_DELAYS(0));
> > + pps->t3 = (val & PANEL_POWER_DOWN_DELAY_MASK) >>
> > +   PANEL_POWER_DOWN_DELAY_SHIFT;
> > + pps->tx = (val & PANEL_LIGHT_OFF_DELAY_MASK) >>
> > +   PANEL_LIGHT_OFF_DELAY_SHIFT;
> > +
> > + val = I915_READ(PP_DIVISOR(0));
> > + pps->divider = (val & PP_REFERENCE_DIVIDER_MASK) >>
> > +        PP_REFERENCE_DIVIDER_SHIFT;
> > + /* Convert from 100ms to 100us units */
> > + pps->t4 = ((val & PANEL_POWER_CYCLE_DELAY_MASK) >>
> > +    PANEL_POWER_CYCLE_DELAY_SHIFT) * 1000;
>
> This should have the +1 offset handling I think.

Ok, will add that.

> Hmm. Looks like we mess that up even for eDP :(
> > +
> > + if (INTEL_INFO(dev_priv)->gen <= 4 &&
> > +     pps->t1_t2 == 0 && pps->t5 == 0 && pps->t3 == 0 && pps->tx == 0) {
> > + DRM_DEBUG_KMS("Panel power timings uninitialized, "
> > +       "setting defaults\n");
> > + /* Set T2 to 40ms and T5 to 200ms in 100 usec units */
> > + pps->t1_t2 = 40 * 10;
> > + pps->t5 = 200 * 10;
> > + /* Set T3 to 35ms and Tx to 200ms in 100 usec units */
> > + pps->t3 = 35 * 10;
> > + pps->tx = 200 * 10;
>
> Not sure where these came from originally. The spgw spec tells us:
>
> min max
> t1 0.5 10
> t2 0 50
> t3 0 50
> t4 200 -
> t5 200 -
> t6 200 -
> t7 0 10
>
> So maybe we should at least set t4=200 here based on the minimum t4
> delay in the spec, probably should add the max t7 time there as well
> as that's what the power cycle delays seems to be really: t4+t7.
> Bspec seems to claim that spgw spec has an upper limit of 400 for this,
> but I can't see that at least in the copy I found.
>
> And maybe bump up t1_t2=60 and t3=50 based on the max delay for those
> in the spec?

Haven't found yet the spec, but the above seem like reasonable
defaults.

>
> Anyways, this is all material for a separate patch for sure.

Yep, I kept the behavior here as-is.

>
> > + }
> > +
> > + DRM_DEBUG_DRIVER("LVDS PPS:t1+t2 %d t3 %d t4 %d t5 %d tx %d "
> > +  "divider %d port %d reset_on_powerdown %d\n",
> > +  pps->t1_t2, pps->t3, pps->t4, pps->t5, pps->tx,
> > +  pps->divider, pps->port, pps->reset_on_powerdown);
> > +}
> > +
> > +static void intel_lvds_pps_init_hw(struct drm_i915_private *dev_priv,
> > +    struct intel_lvds_pps *pps)
> > +{
> > + u32 val;
> > +
> > + val = I915_READ(PP_CONTROL(0));
> > + WARN_ON((val & PANEL_UNLOCK_MASK) != PANEL_UNLOCK_REGS);
> > + if (pps->reset_on_powerdown)
> > + val |= PANEL_POWER_RESET;
>
> Hmm. Maybe we can just always set this bit?

Seems reasonable (for GEN3+), but as also as a follow-up. I just wonder
if the w/a below should be then also applied at the same time. BSpec
doesn't specify the w/a except for IBX, but it seems like the safer
thing to do.

> Hmm, we also totally fail to deal with the related IBX w/a
> in the LVDS code. Should probably fix that up as well as a
> followup.

Ok.

> > + I915_WRITE(PP_CONTROL(0), val);
> > +
> > + I915_WRITE(PP_ON_DELAYS(0), (pps->port << PANEL_PORT_SELECT_SHIFT) |
> > +     (pps->t1_t2 << PANEL_POWER_UP_DELAY_SHIFT) |
> > +     (pps->t5 << PANEL_LIGHT_ON_DELAY_SHIFT));
> > + I915_WRITE(PP_OFF_DELAYS(0), (pps->t3 << PANEL_POWER_DOWN_DELAY_SHIFT) |
> > +      (pps->tx << PANEL_LIGHT_OFF_DELAY_SHIFT));
> > + I915_WRITE(PP_DIVISOR(0), (pps->divider << PP_REFERENCE_DIVIDER_SHIFT) |
> > +   ((pps->t4 / 1000) << PANEL_POWER_CYCLE_DELAY_SHIFT));
>
> DIV_ROUND_UP() I think, and maybe the +1 handling. Though I can't really
> tell if the spec has intended the +1 to be a replacement for rounding
> up, or do we need to do both. Both would seem like the safe choice. Gen2
> Bspec doesn't mention the +1, but it says writing 0 will even abort any
> ongoing delay.

Ok, will change it doing both rounding and +1.

>
> > +}
> > +
> >  static void intel_pre_enable_lvds(struct intel_encoder *encoder)
> >  {
> >   struct intel_lvds_encoder *lvds_encoder = to_lvds_encoder(&encoder->base);
> > @@ -154,7 +237,9 @@ static void intel_pre_enable_lvds(struct intel_encoder *encoder)
> >   assert_pll_disabled(dev_priv, pipe);
> >   }
> >
> > - temp = I915_READ(lvds_encoder->reg);
> > + intel_lvds_pps_init_hw(dev_priv, &lvds_encoder->init_pps);
> > +
> > + temp = lvds_encoder->init_lvds_val;
> >   temp |= LVDS_PORT_EN | LVDS_A0A2_CLKA_POWER_UP;
> >
> >   if (HAS_PCH_CPT(dev)) {
> > @@ -922,18 +1007,6 @@ void intel_lvds_init(struct drm_device *dev)
> >   DRM_DEBUG_KMS("LVDS is not present in VBT, but enabled anyway\n");
> >   }
> >
> > -  /* Set the Panel Power On/Off timings if uninitialized. */
> > - if (INTEL_INFO(dev_priv)->gen < 5 &&
> > -     I915_READ(PP_ON_DELAYS(0)) == 0 && I915_READ(PP_OFF_DELAYS(0)) == 0) {
> > - /* Set T2 to 40ms and T5 to 200ms */
> > - I915_WRITE(PP_ON_DELAYS(0), 0x019007d0);
> > -
> > - /* Set T3 to 35ms and Tx to 200ms */
> > - I915_WRITE(PP_OFF_DELAYS(0), 0x015e07d0);
> > -
> > - DRM_DEBUG_KMS("Panel power timings uninitialized, setting defaults\n");
> > - }
> > -
> >   lvds_encoder = kzalloc(sizeof(*lvds_encoder), GFP_KERNEL);
> >   if (!lvds_encoder)
> >   return;
> > @@ -999,6 +1072,10 @@ void intel_lvds_init(struct drm_device *dev)
> >         dev->mode_config.scaling_mode_property,
> >         DRM_MODE_SCALE_ASPECT);
> >   intel_connector->panel.fitting_mode = DRM_MODE_SCALE_ASPECT;
> > +
> > + intel_lvds_pps_get_hw_state(dev_priv, &lvds_encoder->init_pps);
> > + lvds_encoder->init_lvds_val = lvds;
> > +
> >   /*
> >    * LVDS discovery:
> >    * 1) check for EDID on DDC
> > --
> > 2.5.0
> >
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