Re: [PATCH 11/11] drm/i915/bxt: Enable IPC support

["Lankhorst, Maarten" <maarten.lankhorst@intel.com>]

Mahesh Kumar schreef op wo 05-07-2017 om 20:01 [+0530]:
> From: "Kumar, Mahesh" <mahesh1.kumar@intel.com>
> 
> This patch adds IPC support for platforms. This patch enables IPC
> only for BXT/KBL platform as for SKL recommendation is to keep it
> disabled.
CFL/CNL missing. ;-)
> IPC (Isochronous Priority Control) is the hardware feature, which
> dynamically controls the memory read priority of Display.
> 
> When IPC is enabled, plane read requests are sent at high priority
> until
> filling above the transition watermark, then the requests are sent at
> lower priority until dropping below the level 0 watermark.
> The lower priority requests allow other memory clients to have better
> memory access. When IPC is disabled, all plane read requests are sent
> at
> high priority.
> 
> Changes since V1:
>  - Remove commandline parameter to disable ipc
>  - Address Paulo's comments
> Changes since V2:
>  - Address review comments
>  - Set ipc_enabled flag
> Changes since V3:
>  - move ipc_enabled flag assignment inside intel_ipc_enable function
> Changes since V4:
>  - Re-enable IPC after suspend/resume
> Changes since V5:
>  - Enable IPC for all gen >=9 except SKL
> 
> Signed-off-by: Mahesh Kumar <mahesh1.kumar@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_drv.c      |  4 +++-
>  drivers/gpu/drm/i915/i915_reg.h      |  1 +
>  drivers/gpu/drm/i915/intel_display.c |  1 +
>  drivers/gpu/drm/i915/intel_drv.h     |  1 +
>  drivers/gpu/drm/i915/intel_pm.c      | 16 ++++++++++++++++
>  5 files changed, 22 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_drv.c
> b/drivers/gpu/drm/i915/i915_drv.c
> index 9167a73f3c69..224e00610581 100644
> --- a/drivers/gpu/drm/i915/i915_drv.c
> +++ b/drivers/gpu/drm/i915/i915_drv.c
> @@ -1334,7 +1334,7 @@ int i915_driver_load(struct pci_dev *pdev,
> const struct pci_device_id *ent)
>  
>  	intel_runtime_pm_enable(dev_priv);
>  
> -	dev_priv->ipc_enabled = false;
> +	intel_enable_ipc(dev_priv);
>  
>  	if (IS_ENABLED(CONFIG_DRM_I915_DEBUG))
>  		DRM_INFO("DRM_I915_DEBUG enabled\n");
> @@ -2598,6 +2598,8 @@ static int intel_runtime_resume(struct device
> *kdev)
>  	if (!IS_VALLEYVIEW(dev_priv) && !IS_CHERRYVIEW(dev_priv))
>  		intel_hpd_init(dev_priv);
>  
> +	intel_enable_ipc(dev_priv);
> +
>  	enable_rpm_wakeref_asserts(dev_priv);
>  
>  	if (ret)
> diff --git a/drivers/gpu/drm/i915/i915_reg.h
> b/drivers/gpu/drm/i915/i915_reg.h
> index 64cc674b652a..09af90f8cd0a 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -6728,6 +6728,7 @@ enum {
>  #define  DISP_FBC_WM_DIS		(1<<15)
>  #define DISP_ARB_CTL2	_MMIO(0x45004)
>  #define  DISP_DATA_PARTITION_5_6	(1<<6)
> +#define  DISP_IPC_ENABLE		(1<<3)
>  #define DBUF_CTL	_MMIO(0x45008)
>  #define  DBUF_POWER_REQUEST		(1<<31)
>  #define  DBUF_POWER_STATE		(1<<30)
> diff --git a/drivers/gpu/drm/i915/intel_display.c
> b/drivers/gpu/drm/i915/intel_display.c
> index 0648fd74be87..e610b4395dcc 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -15723,6 +15723,7 @@ void intel_display_resume(struct drm_device
> *dev)
>  	if (!ret)
>  		ret = __intel_display_resume(dev, state, &ctx);
>  
> +	intel_enable_ipc(dev_priv);
>  	drm_modeset_drop_locks(&ctx);
>  	drm_modeset_acquire_fini(&ctx);
>  
> diff --git a/drivers/gpu/drm/i915/intel_drv.h
> b/drivers/gpu/drm/i915/intel_drv.h
> index d17a32437f07..d90b239bd85d 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -1883,6 +1883,7 @@ bool ilk_disable_lp_wm(struct drm_device *dev);
>  int sanitize_rc6_option(struct drm_i915_private *dev_priv, int
> enable_rc6);
>  int skl_check_pipe_max_pixel_rate(struct intel_crtc *intel_crtc,
>  				  struct intel_crtc_state *cstate);
> +void intel_enable_ipc(struct drm_i915_private *dev_priv);
>  static inline int intel_enable_rc6(void)
>  {
>  	return i915.enable_rc6;
> diff --git a/drivers/gpu/drm/i915/intel_pm.c
> b/drivers/gpu/drm/i915/intel_pm.c
> index ad3b3d758d5c..c18695931d33 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -5772,6 +5772,22 @@ void intel_update_watermarks(struct intel_crtc
> *crtc)
>  		dev_priv->display.update_wm(crtc);
>  }
>  
> +void intel_enable_ipc(struct drm_i915_private *dev_priv)
> +{
> +	u32 val;
> +
> +	dev_priv->ipc_enabled = false;
> +	if (INTEL_GEN(dev_priv) < 9 || IS_SKYLAKE(dev_priv))
> +		return;
> +
> +	val = I915_READ(DISP_ARB_CTL2);
> +
> +	val |= DISP_IPC_ENABLE;
> +
> +	I915_WRITE(DISP_ARB_CTL2, val);
> +	dev_priv->ipc_enabled = true;
> +}
> +
>  /*
>   * Lock protecting IPS related data structures
>   */
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