Display WA #1183 was recently added to workaround "Failures when enabling DPLL0 with eDP link rate 2.16 or 4.32 GHz and CD clock frequency 308.57 or 617.14 MHz (CDCLK_CTL CD Frequency Select 10b or 11b) used in this enabling or in previous enabling."

This workaround was designed to minimize the impact only to save the bad case with that link rates. But HW engineers indicated that it should be safe to apply broadly, although they were expecting the DPLL0 link rate to be unchanged on runtime.

We need to cover 2 cases: when we are in fact enabling DPLL0 and when we are just changing the frequency with small differences.

This is based on previous patch by Rodrigo Vivi with suggestions from Ville Syrjälä.

Cc: Arthur J Runyan arthur.j.runyan@intel.com Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: Rodrigo Vivi rodrigo.vivi@intel.com Cc: stable@vger.kernel.org Signed-off-by: Lucas De Marchi lucas.demarchi@intel.com Reviewed-by: Ville Syrjälä ville.syrjala@linux.intel.com Signed-off-by: Rodrigo Vivi rodrigo.vivi@intel.com Link: https://patchwork.freedesktop.org/patch/msgid/20171204232210.4958-1-lucas.de... [ Lucas: Backport to 4.15 adding back variable that has been removed on commits not meant to be backported ] Signed-off-by: Lucas De Marchi lucas.demarchi@intel.com --- drivers/gpu/drm/i915/i915_reg.h | 2 ++ drivers/gpu/drm/i915/intel_cdclk.c | 35 ++++++++++++++++++++++++--------- drivers/gpu/drm/i915/intel_runtime_pm.c | 10 ++++++++++ 3 files changed, 38 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h index 3866c49bc390..333f40bc03bb 100644 --- a/drivers/gpu/drm/i915/i915_reg.h +++ b/drivers/gpu/drm/i915/i915_reg.h @@ -6977,6 +6977,7 @@ enum { #define RESET_PCH_HANDSHAKE_ENABLE (1<<4)

#define GEN8_CHICKEN_DCPR_1 _MMIO(0x46430) +#define SKL_SELECT_ALTERNATE_DC_EXIT (1<<30) #define MASK_WAKEMEM (1<<13)

#define SKL_DFSM _MMIO(0x51000) @@ -8522,6 +8523,7 @@ enum skl_power_gate { #define BXT_CDCLK_CD2X_DIV_SEL_2 (2<<22) #define BXT_CDCLK_CD2X_DIV_SEL_4 (3<<22) #define BXT_CDCLK_CD2X_PIPE(pipe) ((pipe)<<20) +#define CDCLK_DIVMUX_CD_OVERRIDE (1<<19) #define BXT_CDCLK_CD2X_PIPE_NONE BXT_CDCLK_CD2X_PIPE(3) #define BXT_CDCLK_SSA_PRECHARGE_ENABLE (1<<16) #define CDCLK_FREQ_DECIMAL_MASK (0x7ff) diff --git a/drivers/gpu/drm/i915/intel_cdclk.c b/drivers/gpu/drm/i915/intel_cdclk.c index b2a6d62b71c0..60cf4e58389a 100644 --- a/drivers/gpu/drm/i915/intel_cdclk.c +++ b/drivers/gpu/drm/i915/intel_cdclk.c @@ -860,16 +860,10 @@ static void skl_set_preferred_cdclk_vco(struct drm_i915_private *dev_priv,

static void skl_dpll0_enable(struct drm_i915_private *dev_priv, int vco) { - int min_cdclk = skl_calc_cdclk(0, vco); u32 val;

WARN_ON(vco != 8100000 && vco != 8640000);

- /* select the minimum CDCLK before enabling DPLL 0 */ - val = CDCLK_FREQ_337_308 | skl_cdclk_decimal(min_cdclk); - I915_WRITE(CDCLK_CTL, val); - POSTING_READ(CDCLK_CTL); - /* * We always enable DPLL0 with the lowest link rate possible, but still * taking into account the VCO required to operate the eDP panel at the @@ -923,7 +917,7 @@ static void skl_set_cdclk(struct drm_i915_private *dev_priv, { int cdclk = cdclk_state->cdclk; int vco = cdclk_state->vco; - u32 freq_select, pcu_ack; + u32 freq_select, pcu_ack, cdclk_ctl; int ret;

WARN_ON((cdclk == 24000) != (vco == 0)); @@ -940,7 +934,7 @@ static void skl_set_cdclk(struct drm_i915_private *dev_priv, return; }

- /* set CDCLK_CTL */ + /* Choose frequency for this cdclk */ switch (cdclk) { case 450000: case 432000: @@ -968,10 +962,33 @@ static void skl_set_cdclk(struct drm_i915_private *dev_priv, dev_priv->cdclk.hw.vco != vco) skl_dpll0_disable(dev_priv);

+ cdclk_ctl = I915_READ(CDCLK_CTL); + + if (dev_priv->cdclk.hw.vco != vco) { + /* Wa Display #1183: skl,kbl,cfl */ + cdclk_ctl &= ~(CDCLK_FREQ_SEL_MASK | CDCLK_FREQ_DECIMAL_MASK); + cdclk_ctl |= freq_select | skl_cdclk_decimal(cdclk); + I915_WRITE(CDCLK_CTL, cdclk_ctl); + } + + /* Wa Display #1183: skl,kbl,cfl */ + cdclk_ctl |= CDCLK_DIVMUX_CD_OVERRIDE; + I915_WRITE(CDCLK_CTL, cdclk_ctl); + POSTING_READ(CDCLK_CTL); + if (dev_priv->cdclk.hw.vco != vco) skl_dpll0_enable(dev_priv, vco);

- I915_WRITE(CDCLK_CTL, freq_select | skl_cdclk_decimal(cdclk)); + /* Wa Display #1183: skl,kbl,cfl */ + cdclk_ctl &= ~(CDCLK_FREQ_SEL_MASK | CDCLK_FREQ_DECIMAL_MASK); + I915_WRITE(CDCLK_CTL, cdclk_ctl); + + cdclk_ctl |= freq_select | skl_cdclk_decimal(cdclk); + I915_WRITE(CDCLK_CTL, cdclk_ctl); + + /* Wa Display #1183: skl,kbl,cfl */ + cdclk_ctl &= ~CDCLK_DIVMUX_CD_OVERRIDE; + I915_WRITE(CDCLK_CTL, cdclk_ctl); POSTING_READ(CDCLK_CTL);

/* inform PCU of the change */ diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c index 8af286c63d3b..e0bc2debdad0 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.c +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c @@ -598,6 +598,11 @@ void gen9_enable_dc5(struct drm_i915_private *dev_priv)

DRM_DEBUG_KMS("Enabling DC5\n");

+ /* Wa Display #1183: skl,kbl,cfl */ + if (IS_GEN9_BC(dev_priv)) + I915_WRITE(GEN8_CHICKEN_DCPR_1, I915_READ(GEN8_CHICKEN_DCPR_1) | + SKL_SELECT_ALTERNATE_DC_EXIT); + gen9_set_dc_state(dev_priv, DC_STATE_EN_UPTO_DC5); }

@@ -625,6 +630,11 @@ void skl_disable_dc6(struct drm_i915_private *dev_priv) { DRM_DEBUG_KMS("Disabling DC6\n");

+ /* Wa Display #1183: skl,kbl,cfl */ + if (IS_GEN9_BC(dev_priv)) + I915_WRITE(GEN8_CHICKEN_DCPR_1, I915_READ(GEN8_CHICKEN_DCPR_1) | + SKL_SELECT_ALTERNATE_DC_EXIT); + gen9_set_dc_state(dev_priv, DC_STATE_DISABLE); }