Re: [Inter-gfx][PATCH][v3 3/4] drm/i915: add set_tail hook in struct intel_ring_buffer

From: Zhenyu Wang <zhenyuw@linux.intel.com>
To: "Xiang, Haihao" <haihao.xiang@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [Inter-gfx][PATCH][v3 3/4] drm/i915: add set_tail hook in struct intel_ring_buffer
Date: Thu, 16 Sep 2010 12:21:21 +0800	[thread overview]
Message-ID: <20100916042121.GN9765@zhen-devel.sh.intel.com> (raw)
In-Reply-To: <1284604993-2810-3-git-send-email-haihao.xiang@intel.com>

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On 2010.09.16 10:43:12 +0800, Xiang, Haihao wrote:
> This is prepared for video codec ring buffer on Sandybridge. It is
> needed to read/write more than one register to move the tail pointer of
> the video codec ring on Sandybridge.

Do we really need new 'set_tail'? Isn't advance_ring used for set ring tail?

Sandybridge workaround can be put into advance_ring, so your 'set_tail''s only
left usage is for initialization. Is that workaround even needed for initial
0 setting? Or can't that be done in init function by using advance_ring?

> 
> Signed-off-by: Xiang, Haihao <haihao.xiang@intel.com>
> Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/intel_ringbuffer.c |   22 +++++++++++++++++-----
>  drivers/gpu/drm/i915/intel_ringbuffer.h |    2 ++
>  2 files changed, 19 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.c b/drivers/gpu/drm/i915/intel_ringbuffer.c
> index a9d4f5b..0a65182 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.c
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.c
> @@ -134,6 +134,12 @@ static unsigned int render_ring_get_tail(struct drm_device *dev,
>  	return I915_READ(PRB0_TAIL) & TAIL_ADDR;
>  }
>  
> +static inline void render_ring_set_tail(struct drm_device *dev, u32 value)
> +{
> +	drm_i915_private_t *dev_priv = dev->dev_private;
> +	I915_WRITE(PRB0_TAIL, value);
> +}
> +
>  static unsigned int render_ring_get_active_head(struct drm_device *dev,
>  		struct intel_ring_buffer *ring)
>  {
> @@ -146,8 +152,7 @@ static unsigned int render_ring_get_active_head(struct drm_device *dev,
>  static void render_ring_advance_ring(struct drm_device *dev,
>  		struct intel_ring_buffer *ring)
>  {
> -	drm_i915_private_t *dev_priv = dev->dev_private;
> -	I915_WRITE(PRB0_TAIL, ring->tail);
> +	render_ring_set_tail(dev, ring->tail);
>  }
>  
>  static int init_ring_common(struct drm_device *dev,
> @@ -161,7 +166,7 @@ static int init_ring_common(struct drm_device *dev,
>  	/* Stop the ring if it's running. */
>  	I915_WRITE(ring->regs.ctl, 0);
>  	I915_WRITE(ring->regs.head, 0);
> -	I915_WRITE(ring->regs.tail, 0);
> +	ring->set_tail(dev, 0);
>  
>  	/* Initialize the ring. */
>  	I915_WRITE(ring->regs.start, obj_priv->gtt_offset);
> @@ -404,6 +409,12 @@ static inline unsigned int bsd_ring_get_tail(struct drm_device *dev,
>  	return I915_READ(BSD_RING_TAIL) & TAIL_ADDR;
>  }
>  
> +static inline void bsd_ring_set_tail(struct drm_device *dev, u32 value)
> +{
> +	drm_i915_private_t *dev_priv = dev->dev_private;
> +	I915_WRITE(BSD_RING_TAIL, value);
> +}
> +
>  static inline unsigned int bsd_ring_get_active_head(struct drm_device *dev,
>  		struct intel_ring_buffer *ring)
>  {
> @@ -414,8 +425,7 @@ static inline unsigned int bsd_ring_get_active_head(struct drm_device *dev,
>  static inline void bsd_ring_advance_ring(struct drm_device *dev,
>  		struct intel_ring_buffer *ring)
>  {
> -	drm_i915_private_t *dev_priv = dev->dev_private;
> -	I915_WRITE(BSD_RING_TAIL, ring->tail);
> +	bsd_ring_set_tail(dev, ring->tail);
>  }
>  
>  static int init_bsd_ring(struct drm_device *dev,
> @@ -820,6 +830,7 @@ static struct intel_ring_buffer render_ring = {
>  	.init			= init_render_ring,
>  	.get_head		= render_ring_get_head,
>  	.get_tail		= render_ring_get_tail,
> +	.set_tail		= render_ring_set_tail,
>  	.get_active_head	= render_ring_get_active_head,
>  	.advance_ring		= render_ring_advance_ring,
>  	.flush			= render_ring_flush,
> @@ -857,6 +868,7 @@ static struct intel_ring_buffer bsd_ring = {
>  	.init			= init_bsd_ring,
>  	.get_head		= bsd_ring_get_head,
>  	.get_tail		= bsd_ring_get_tail,
> +	.set_tail		= bsd_ring_set_tail,
>  	.get_active_head	= bsd_ring_get_active_head,
>  	.advance_ring		= bsd_ring_advance_ring,
>  	.flush			= bsd_ring_flush,
> diff --git a/drivers/gpu/drm/i915/intel_ringbuffer.h b/drivers/gpu/drm/i915/intel_ringbuffer.h
> index df7acc5..f89e528 100644
> --- a/drivers/gpu/drm/i915/intel_ringbuffer.h
> +++ b/drivers/gpu/drm/i915/intel_ringbuffer.h
> @@ -44,6 +44,8 @@ struct  intel_ring_buffer {
>  			struct intel_ring_buffer *ring);
>  	unsigned int	(*get_tail)(struct drm_device *dev,
>  			struct intel_ring_buffer *ring);
> +	void		(*set_tail)(struct drm_device *dev,
> +			u32 value);
>  	unsigned int	(*get_active_head)(struct drm_device *dev,
>  			struct intel_ring_buffer *ring);
>  	void		(*advance_ring)(struct drm_device *dev,
> -- 
> 1.7.0.4
> 
> _______________________________________________
> Intel-gfx mailing list
> Intel-gfx@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/intel-gfx

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