[Intel-gfx] [PATCH v2] drm/i915: only enable sdvo hotplug irq if needed

[Daniel Vetter]

On Wed, Aug 29, 2012 at 02:08:42PM +0300, Jani Nikula wrote:
> Avoid constant wakeups caused by noisy irq lines when we don't even care
> about the irq. This should be particularly useful for i945g/gm where the
> hotplug has been disabled:
> 
> commit 768b107e4b3be0acf6f58e914afe4f337c00932b
> Author: Daniel Vetter <daniel.vetter at ffwll.ch>
> Date:   Fri May 4 11:29:56 2012 +0200
> 
>     drm/i915: disable sdvo hotplug on i945g/gm
> 
> v2: While at it, remove the bogus hotplug_active read, and do not mask
> hotplug_active[0] before checking whether the irq is needed, per discussion
> with Daniel on IRC.
> 
> Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=38442
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>
> 
> ---
> 
> N.B. This really needs a Tested-by from the bug reporter.
Picked up for -fixes (with the tested-by + cc: stable added), thanks for
the patch.
-Daniel
> ---
>  drivers/gpu/drm/i915/intel_sdvo.c |   15 ++++++---------
>  1 file changed, 6 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_sdvo.c b/drivers/gpu/drm/i915/intel_sdvo.c
> index d81bb0b..123afd3 100644
> --- a/drivers/gpu/drm/i915/intel_sdvo.c
> +++ b/drivers/gpu/drm/i915/intel_sdvo.c
> @@ -2573,7 +2573,6 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob)
>  		hotplug_mask = intel_sdvo->is_sdvob ?
>  			SDVOB_HOTPLUG_INT_STATUS_I915 : SDVOC_HOTPLUG_INT_STATUS_I915;
>  	}
> -	dev_priv->hotplug_supported_mask |= hotplug_mask;
>  
>  	drm_encoder_helper_add(&intel_encoder->base, &intel_sdvo_helper_funcs);
>  
> @@ -2581,14 +2580,6 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob)
>  	if (!intel_sdvo_get_capabilities(intel_sdvo, &intel_sdvo->caps))
>  		goto err;
>  
> -	/* Set up hotplug command - note paranoia about contents of reply.
> -	 * We assume that the hardware is in a sane state, and only touch
> -	 * the bits we think we understand.
> -	 */
> -	intel_sdvo_get_value(intel_sdvo, SDVO_CMD_GET_ACTIVE_HOT_PLUG,
> -			     &intel_sdvo->hotplug_active, 2);
> -	intel_sdvo->hotplug_active[0] &= ~0x3;
> -
>  	if (intel_sdvo_output_setup(intel_sdvo,
>  				    intel_sdvo->caps.output_flags) != true) {
>  		DRM_DEBUG_KMS("SDVO output failed to setup on %s\n",
> @@ -2596,6 +2587,12 @@ bool intel_sdvo_init(struct drm_device *dev, uint32_t sdvo_reg, bool is_sdvob)
>  		goto err;
>  	}
>  
> +	/* Only enable the hotplug irq if we need it, to work around noisy
> +	 * hotplug lines.
> +	 */
> +	if (intel_sdvo->hotplug_active[0])
> +		dev_priv->hotplug_supported_mask |= hotplug_mask;
> +
>  	intel_sdvo_select_ddc_bus(dev_priv, intel_sdvo, sdvo_reg);
>  
>  	/* Set the input timing to the screen. Assume always input 0. */
> -- 
> 1.7.9.5
> 

-- 
Daniel Vetter
Mail: daniel at ffwll.ch
Mobile: +41 (0)79 365 57 48