On Fri, Aug 31, 2018 at 12:25:31PM +0200, Maarten Lankhorst wrote:
> Op 24-08-18 om 11:32 schreef Mahesh Kumar:
> > IPC may cause underflows if not used with dual channel symmetric
> > memory configuration. Disable IPC for non symmetric configurations in
> > affected platforms.
> > Display WA #1141
> >
> > Changes Since V1:
> >  - Re-arrange the code.
> >  - update wrapper to return if memory is symmetric (Rodrigo)
> >
> > Signed-off-by: Mahesh Kumar <mahesh1.ku...@intel.com>
> > ---
> >  drivers/gpu/drm/i915/i915_drv.c | 27 ++++++++++++++++++++++-----
> >  drivers/gpu/drm/i915/i915_drv.h |  1 +
> >  drivers/gpu/drm/i915/intel_pm.c |  5 +++++
> >  3 files changed, 28 insertions(+), 5 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/i915/i915_drv.c 
> > b/drivers/gpu/drm/i915/i915_drv.c
> > index 2bc74c01a0e5..61d756ae7bf0 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.c
> > +++ b/drivers/gpu/drm/i915/i915_drv.c
> > @@ -1154,21 +1154,32 @@ skl_dram_get_channel_info(struct dram_channel_info 
> > *ch, u32 val)
> >     return 0;
> >  }
> >  
> > +static bool
> > +intel_is_dram_symmetric(u32 val_ch0, u32 val_ch1,
> > +                   struct dram_channel_info *ch0)
> > +{
> > +   return (val_ch0 == val_ch1 &&
> > +           (ch0->s_info.size == 0 ||
> > +            (ch0->l_info.size == ch0->s_info.size &&
> > +             ch0->l_info.width == ch0->s_info.width &&
> > +             ch0->l_info.rank == ch0->s_info.rank)));
> > +}
> > +
> >  static int
> >  skl_dram_get_channels_info(struct drm_i915_private *dev_priv)
> >  {
> >     struct dram_info *dram_info = &dev_priv->dram_info;
> >     struct dram_channel_info ch0, ch1;
> > -   u32 val;
> > +   u32 val_ch0, val_ch1;
> >     int ret;
> >  
> > -   val = I915_READ(SKL_MAD_DIMM_CH0_0_0_0_MCHBAR_MCMAIN);
> > -   ret = skl_dram_get_channel_info(&ch0, val);
> > +   val_ch0 = I915_READ(SKL_MAD_DIMM_CH0_0_0_0_MCHBAR_MCMAIN);
> > +   ret = skl_dram_get_channel_info(&ch0, val_ch0);
> >     if (ret == 0)
> >             dram_info->num_channels++;
> >  
> > -   val = I915_READ(SKL_MAD_DIMM_CH1_0_0_0_MCHBAR_MCMAIN);
> > -   ret = skl_dram_get_channel_info(&ch1, val);
> > +   val_ch1 = I915_READ(SKL_MAD_DIMM_CH1_0_0_0_MCHBAR_MCMAIN);
> > +   ret = skl_dram_get_channel_info(&ch1, val_ch1);
> >     if (ret == 0)
> >             dram_info->num_channels++;
> >  
> > @@ -1198,6 +1209,12 @@ skl_dram_get_channels_info(struct drm_i915_private 
> > *dev_priv)
> >     if (ch0.is_16gb_dimm || ch1.is_16gb_dimm)
> >             dram_info->is_16gb_dimm = true;
> >  
> > +   dev_priv->dram_info.symmetric_memory = intel_is_dram_symmetric(val_ch0,
> > +                                                                  val_ch1,
> > +                                                                  &ch0);
> > +
> > +   DRM_DEBUG_KMS("memory configuration is %sSymmetric memory\n",
> > +                 dev_priv->dram_info.symmetric_memory ? "" : "not ");
> >     return 0;
> >  }
> >  
> > diff --git a/drivers/gpu/drm/i915/i915_drv.h 
> > b/drivers/gpu/drm/i915/i915_drv.h
> > index 6c432684c721..e7faa046f78a 100644
> > --- a/drivers/gpu/drm/i915/i915_drv.h
> > +++ b/drivers/gpu/drm/i915/i915_drv.h
> > @@ -1955,6 +1955,7 @@ struct drm_i915_private {
> >                     I915_DRAM_RANK_DUAL
> >             } rank;
> >             u32 bandwidth_kbps;
> > +           bool symmetric_memory;
> >     } dram_info;
> >  
> >     struct i915_runtime_pm runtime_pm;
> > diff --git a/drivers/gpu/drm/i915/intel_pm.c 
> > b/drivers/gpu/drm/i915/intel_pm.c
> > index 77970e38d939..c27646fb4cec 100644
> > --- a/drivers/gpu/drm/i915/intel_pm.c
> > +++ b/drivers/gpu/drm/i915/intel_pm.c
> > @@ -6124,6 +6124,11 @@ void intel_enable_ipc(struct drm_i915_private 
> > *dev_priv)
> >     if (IS_SKYLAKE(dev_priv))
> >             dev_priv->ipc_enabled = false;
> >  
> > +   /* Display WA #1141: SKL:all KBL:all CFL */
> > +   if ((IS_KABYLAKE(dev_priv) || IS_COFFEELAKE(dev_priv)) &&
> > +       !dev_priv->dram_info.symmetric_memory)
> > +           dev_priv->ipc_enabled = false;
> > +
> >     val = I915_READ(DISP_ARB_CTL2);
> >  
> >     if (dev_priv->ipc_enabled)
> 
> Patch series looks good with minor nit in 3/5 fixed.
> 
> 
> Reviewed-by: Maarten Lankhorst <maarten.lankho...@linux.intel.com>

Series pushed to dinq. Thanks for patches and reviews.

> 
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