[Intel-gfx] [PATCH] drm/i915: Enable GSE interrupt on BDW+

[Daniel Vetter]

On Wed, Dec 02, 2015 at 12:17:10AM +0200, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> We've never actually enabled or unmasked the GSE interrupt on BDW+,
> even though the interrupt handler was always prepared for it.
> Let's enable it and see what happens.
> 
> Credit to Mark Kettenis who fixed this in the OpenBSD fork of the
> driver. He reports that it fixed the "ACPI _BCM/_BCQ-based
> brightness mechanism on a MacBookPro12,1 and a 3rd gen Lenovo X1
> Carbon" for them.
> 
> References: http://lists.freedesktop.org/archives/intel-gfx/2015-December/081799.html
> Reported-by: Mark Kettenis <mark.kettenis at xs4all.nl>
> Cc: Mark Kettenis <mark.kettenis at xs4all.nl>
> Cc: Jani Nikula <jani.nikula at linux.intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Oh dear, there probably goes all our backlight fun. And how did we miss
that DE_MISC wasn't enabled for this long ... but there's indeed nothing
else interesting in there. Imo -fixes, and cc: stable as soon as someone
confirms it fixes something on our end too.

Reviewed-by: Daniel Vetter <daniel.vetter at ffwll.ch>

And big kudos to Mark!

Cheers, Daniel

> ---
>  drivers/gpu/drm/i915/i915_irq.c | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
> index e88d692583a5..ccdac24039e8 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -3655,6 +3655,7 @@ static void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
>  	uint32_t de_pipe_enables;
>  	u32 de_port_masked = GEN8_AUX_CHANNEL_A;
>  	u32 de_port_enables;
> +	u32 de_misc_masked = GEN8_DE_MISC_GSE;
>  	enum pipe pipe;
>  
>  	if (INTEL_INFO(dev_priv)->gen >= 9) {
> @@ -3690,6 +3691,7 @@ static void gen8_de_irq_postinstall(struct drm_i915_private *dev_priv)
>  					  de_pipe_enables);
>  
>  	GEN5_IRQ_INIT(GEN8_DE_PORT_, ~de_port_masked, de_port_enables);
> +	GEN5_IRQ_INIT(GEN8_DE_MISC_, ~de_misc_masked, de_misc_masked);
>  }
>  
>  static int gen8_irq_postinstall(struct drm_device *dev)
> -- 
> 2.4.10
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch