Re: [PATCH 02/10] drm/i915: Support PCH no display

["Ville Syrjälä" <ville.syrjala@linux.intel.com>]

On Fri, Mar 15, 2013 at 11:17:47AM -0700, Ben Widawsky wrote:
> GEN supports a fusing option which subtracts the PCH display (making the
> CPU display also useless). In this configuration MMIO which gets decoded
> to a certain range will hang the CPU.
> 
> For us, this is sort of the equivalent of having no pipes, and we can
> easily modify some code to not do certain things with no pipes.
> 
> Signed-off-by: Ben Widawsky <ben@bwidawsk.net>
> ---
>  drivers/gpu/drm/i915/i915_dma.c      | 20 ++++++++++++++------
>  drivers/gpu/drm/i915/intel_crt.c     |  3 +++
>  drivers/gpu/drm/i915/intel_display.c | 10 ++++++++--
>  drivers/gpu/drm/i915/intel_fb.c      |  3 +++
>  drivers/gpu/drm/i915/intel_overlay.c |  3 +++
>  5 files changed, 31 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
> index ebcfe2e..d925504 100644
> --- a/drivers/gpu/drm/i915/i915_dma.c
> +++ b/drivers/gpu/drm/i915/i915_dma.c
> @@ -1322,6 +1322,10 @@ static int i915_load_modeset_init(struct drm_device *dev)
>  	/* Always safe in the mode setting case. */
>  	/* FIXME: do pre/post-mode set stuff in core KMS code */
>  	dev->vblank_disable_allowed = 1;
> +	if (INTEL_INFO(dev)->num_pipes == 0) {
> +		dev_priv->mm.suspended = 0;
> +		return 0;
> +	}
>  
>  	ret = intel_fbdev_init(dev);
>  	if (ret)
> @@ -1630,9 +1634,11 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
>  	mutex_init(&dev_priv->rps.hw_lock);
>  	mutex_init(&dev_priv->modeset_restore_lock);
>  
> -	ret = drm_vblank_init(dev, INTEL_INFO(dev)->num_pipes);
> -	if (ret)
> -		goto out_gem_unload;
> +	if (INTEL_INFO(dev)->num_pipes) {
> +		ret = drm_vblank_init(dev, INTEL_INFO(dev)->num_pipes);
> +		if (ret)
> +			goto out_gem_unload;
> +	}
>  
>  	/* Start out suspended */
>  	dev_priv->mm.suspended = 1;
> @@ -1647,9 +1653,11 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
>  
>  	i915_setup_sysfs(dev);
>  
> -	/* Must be done after probing outputs */
> -	intel_opregion_init(dev);
> -	acpi_video_register();
> +	if (INTEL_INFO(dev)->num_pipes) {
> +		/* Must be done after probing outputs */
> +		intel_opregion_init(dev);
> +		acpi_video_register();
> +	}
>  
>  	if (IS_GEN5(dev))
>  		intel_gpu_ips_init(dev_priv);
> diff --git a/drivers/gpu/drm/i915/intel_crt.c b/drivers/gpu/drm/i915/intel_crt.c
> index cfc9687..e794c6c 100644
> --- a/drivers/gpu/drm/i915/intel_crt.c
> +++ b/drivers/gpu/drm/i915/intel_crt.c
> @@ -736,6 +736,9 @@ void intel_crt_init(struct drm_device *dev)
>  	if (dmi_check_system(intel_no_crt))
>  		return;
>  
> +	if (INTEL_INFO(dev)->num_pipes == 0)
> +		return;
> +
>  	crt = kzalloc(sizeof(struct intel_crt), GFP_KERNEL);
>  	if (!crt)
>  		return;
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 23379e7..d6dbffd 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -7682,6 +7682,9 @@ intel_modeset_check_state(struct drm_device *dev)
>  	struct intel_encoder *encoder;
>  	struct intel_connector *connector;
>  
> +	if (INTEL_INFO(dev)->num_pipes == 0)
> +		return;
> +
>  	list_for_each_entry(connector, &dev->mode_config.connector_list,
>  			    base.head) {
>  		/* This also checks the encoder/connector hw state with the
> @@ -8326,7 +8329,9 @@ static void intel_setup_outputs(struct drm_device *dev)
>  	if (!(HAS_DDI(dev) && (I915_READ(DDI_BUF_CTL(PORT_A)) & DDI_A_4_LANES)))
>  		intel_crt_init(dev);
>  
> -	if (HAS_DDI(dev)) {
> +	if (INTEL_INFO(dev)->num_pipes == 0) {
> +		DRM_DEBUG_KMS("Skipping output detection\n");

Wouldn't it be better to skip intel_setup_outputs() entirely? You could
then drop the intel_crt_init() hunk too.

> +	} else if (HAS_DDI(dev)) {
>  		int found;
>  
>  		/* Haswell uses DDI functions to detect digital outputs */
> @@ -8443,7 +8448,8 @@ static void intel_setup_outputs(struct drm_device *dev)
>  
>  	intel_init_pch_refclk(dev);
>  
> -	drm_helper_move_panel_connectors_to_head(dev);
> +	if (INTEL_INFO(dev)->num_pipes)
> +		drm_helper_move_panel_connectors_to_head(dev);
>  }
>  
>  static void intel_user_framebuffer_destroy(struct drm_framebuffer *fb)
> diff --git a/drivers/gpu/drm/i915/intel_fb.c b/drivers/gpu/drm/i915/intel_fb.c
> index dcdb1d3..5f825c2 100644
> --- a/drivers/gpu/drm/i915/intel_fb.c
> +++ b/drivers/gpu/drm/i915/intel_fb.c
> @@ -295,6 +295,9 @@ void intel_fb_restore_mode(struct drm_device *dev)
>  	struct drm_mode_config *config = &dev->mode_config;
>  	struct drm_plane *plane;
>  
> +	if (!INTEL_INFO(dev)->num_pipes)
> +		return;
> +
>  	drm_modeset_lock_all(dev);
>  
>  	ret = drm_fb_helper_restore_fbdev_mode(&dev_priv->fbdev->helper);
> diff --git a/drivers/gpu/drm/i915/intel_overlay.c b/drivers/gpu/drm/i915/intel_overlay.c
> index 67a2501..e7fbf2e 100644
> --- a/drivers/gpu/drm/i915/intel_overlay.c
> +++ b/drivers/gpu/drm/i915/intel_overlay.c
> @@ -1323,6 +1323,9 @@ void intel_setup_overlay(struct drm_device *dev)
>  	if (!HAS_OVERLAY(dev))
>  		return;
>  
> +	if (INTEL_INFO(dev)->num_pipes == 0)
> +		return;
> +
>  	overlay = kzalloc(sizeof(struct intel_overlay), GFP_KERNEL);
>  	if (!overlay)
>  		return;
> -- 
> 1.8.1.5
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

-- 
Ville Syrjälä
Intel OTC