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.kumar@xxxxxxxxx>
> ---
> 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.lankhorst@xxxxxxxxxxxxxxx>
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