On Thu, Nov 05, 2020 at 10:47:15AM +0530, Anshuman Gupta wrote:
On 2020-11-03 at 17:06:42 -0500, Rodrigo Vivi wrote:
On Fri, Oct 30, 2020 at 11:46:58AM +0530, Anshuman Gupta wrote:
> From: Bob Paauwe <bob.j.paa...@intel.com>
>
> The WA specifies that we need to toggle a SDE chicken bit on and then
> off as the final step in preparation for s0ix entry.
>
>     Bspec: 33450
>     Bspec: 8402
>
> However, something is happening after we toggle the bit that causes
> the WA to be invalidated. This makes dispcnlunit1_cp_xosc_clkreq
> active being already in s0ix state i.e SLP_S0 counter incremented.
> Tweaking the Wa_14010685332 by setting the bit on suspend and clearing
> it on resume turns down the dispcnlunit1_cp_xosc_clkreq.
> B.Spec has Documented this tweaked sequence of WA as an alternative.
> Let keep this tweaked WA for Gen11 platforms and keep untweaked WA for
> other platforms which never observed this issue.
>
> v2 (MattR):
>  - Change the comment on the workaround to give PCH names rather than
>    platform names.  Although the bspec is setup to list workarounds by
>    platform, the hardware team has confirmed that the actual issue being
>    worked around here is something that was introduced back in the
>    Cannon Lake PCH and carried forward to subsequent PCH's.
>  - Extend the untweaked version of the workaround to include  PCH_CNP as
>    well.  Note that since PCH_CNP is used to represent CMP, this will
>    apply on CML and some variants of RKL too.
>  - Cap the untweaked version of the workaround so that it won't apply to
>    "fake" PCH's (i.e., DG1).  The issue we're working around really is
>    an issue in the PCH itself, not the South Display, so it shouldn't
>    apply when there isn't a real PCH.
>
> Cc: Rodrigo Vivi <rodrigo.v...@intel.com>
> Signed-off-by: Bob Paauwe <bob.j.paa...@intel.com>
> Signed-off-by: Anshuman Gupta <anshuman.gu...@intel.com>
> Signed-off-by: Matt Roper <matthew.d.ro...@intel.com>
> ---
>  .../drm/i915/display/intel_display_power.c    | 21 +++++++++++++++++--
>  drivers/gpu/drm/i915/i915_irq.c               |  6 ++++--
>  2 files changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_power.c 
b/drivers/gpu/drm/i915/display/intel_display_power.c
> index 689922480661..d2a6518329d7 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_power.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_power.c
> @@ -5858,17 +5858,34 @@ static void intel_power_domains_verify_state(struct 
drm_i915_private *i915)
>
>  void intel_display_power_suspend_late(struct drm_i915_private *i915)
>  {
> -  if (INTEL_GEN(i915) >= 11 || IS_GEN9_LP(i915))
> +  u32 val;
> +
> +  if (INTEL_GEN(i915) >= 11 || IS_GEN9_LP(i915)) {
>            bxt_enable_dc9(i915);
> -  else if (IS_HASWELL(i915) || IS_BROADWELL(i915))
> +          /* Tweaked Wa_14010685332:icp,jsp,mcc */
> +          if (INTEL_PCH_TYPE(i915) >= PCH_ICP && INTEL_PCH_TYPE(i915) <= 
PCH_MCC) {
> +                  val = intel_de_read(i915, SOUTH_CHICKEN1);
> +                  val |= SBCLK_RUN_REFCLK_DIS;
> +                  intel_de_write(i915, SOUTH_CHICKEN1, val);

could we use intel_de_rmw here?
May be i had misunderstod it earlier, i thought it was your recommendation
to use manual read, modify write without using intel_uncore_rmw(),
Was the actual idea to use intel_de_rmw flavour of API instead of 
intel_uncore_rmw?

intel_de_rmw() is the exact equivalent of what's done above. As this is
a PCH register I think it would be appropriate to use intel_de_*

Jani, is intel_de_* meant to be only a shortcut or are we going to
enforce accessing only DE registers with it?

Also would it require to use at original Wa in gen11_display_irq_reset as well?

since that file is outside display/ we'd need to be very careful in using
intel_de_* there.

thanks
Lucas De Marchi

Thanks,
Anshuman Gupta.

> +          }
> +  } else if (IS_HASWELL(i915) || IS_BROADWELL(i915)) {
>            hsw_enable_pc8(i915);
> +  }
>  }
>
>  void intel_display_power_resume_early(struct drm_i915_private *i915)
>  {
> +  u32 val;
> +
>    if (INTEL_GEN(i915) >= 11 || IS_GEN9_LP(i915)) {
>            gen9_sanitize_dc_state(i915);
>            bxt_disable_dc9(i915);
> +          /* Tweaked Wa_14010685332:icp,jsp,mcc */
> +          if (INTEL_PCH_TYPE(i915) >= PCH_ICP && INTEL_PCH_TYPE(i915) <= 
PCH_MCC) {
> +                  val = intel_de_read(i915, SOUTH_CHICKEN1);
> +                  val &= ~SBCLK_RUN_REFCLK_DIS;
> +                  intel_de_write(i915, SOUTH_CHICKEN1, val);

and here?

sorry for not having spotted that sooner.

> +          }
>    } else if (IS_HASWELL(i915) || IS_BROADWELL(i915)) {
>            hsw_disable_pc8(i915);
>    }
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index dc33c96d741d..410c03624c6a 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -3055,8 +3055,10 @@ static void gen11_display_irq_reset(struct 
drm_i915_private *dev_priv)
>    if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP)
>            GEN3_IRQ_RESET(uncore, SDE);
>
> -  /* Wa_14010685332:icl,jsl,ehl,tgl,rkl */
> -  if (INTEL_PCH_TYPE(dev_priv) >= PCH_ICP) {
> +  /* Wa_14010685332:cnp/cmp,tgp,adp */
> +  if (INTEL_PCH_TYPE(dev_priv) == PCH_CNP ||
> +      (INTEL_PCH_TYPE(dev_priv) >= PCH_TGP &&
> +       INTEL_PCH_TYPE(dev_priv) < PCH_DG1)) {
>            intel_uncore_rmw(uncore, SOUTH_CHICKEN1,
>                             SBCLK_RUN_REFCLK_DIS, SBCLK_RUN_REFCLK_DIS);
>            intel_uncore_rmw(uncore, SOUTH_CHICKEN1,
> --
> 2.26.2
>
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