Re: [PATCH v3 9/9] omap3isp: preview: Shorten shadow update delay

[Sakari Ailus <sakari.ailus@iki.fi>]

Hi Laurent,

Many thanks for the patch!!

On Mon, Apr 16, 2012 at 03:29:54PM +0200, Laurent Pinchart wrote:
> When applications modify preview engine parameters, the new values are
> applied to the hardware by the preview engine interrupt handler during
> vertical blanking. If the parameters are being changed when the
> interrupt handler is called, it just delays applying the parameters
> until the next frame.
> 
> If an application modifies the parameters for every frame, and the
> preview engine interrupt is triggerred synchronously, the parameters are
> never applied to the hardware.
> 
> Fix this by storing new parameters in a shadow copy, and switch the
> active parameters with the shadow values atomically.
> 
> Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
> ---
>  drivers/media/video/omap3isp/isppreview.c |  298 +++++++++++++++++++----------
>  drivers/media/video/omap3isp/isppreview.h |   21 ++-
>  2 files changed, 212 insertions(+), 107 deletions(-)
> 
> diff --git a/drivers/media/video/omap3isp/isppreview.c b/drivers/media/video/omap3isp/isppreview.c
> index e12df2c..5ccfe46 100644
> --- a/drivers/media/video/omap3isp/isppreview.c
> +++ b/drivers/media/video/omap3isp/isppreview.c
> @@ -649,12 +649,18 @@ preview_config_rgb_to_ycbcr(struct isp_prev_device *prev, const void *prev_csc)

Not related to this patch, but shouldn't the above function be called
preview_config_csc()?

>  static void
>  preview_update_contrast(struct isp_prev_device *prev, u8 contrast)
>  {
> -	struct prev_params *params = &prev->params;
> +	struct prev_params *params;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&prev->params.lock, flags);
> +	params = (prev->params.active & OMAP3ISP_PREV_CONTRAST)
> +	       ? &prev->params.params[0] : &prev->params.params[1];
>  
>  	if (params->contrast != (contrast * ISPPRV_CONTRAST_UNITS)) {
>  		params->contrast = contrast * ISPPRV_CONTRAST_UNITS;
> -		prev->update |= OMAP3ISP_PREV_CONTRAST;
> +		params->update |= OMAP3ISP_PREV_CONTRAST;
>  	}
> +	spin_unlock_irqrestore(&prev->params.lock, flags);
>  }
>  
>  /*
> @@ -681,12 +687,18 @@ preview_config_contrast(struct isp_prev_device *prev, const void *params)
>  static void
>  preview_update_brightness(struct isp_prev_device *prev, u8 brightness)
>  {
> -	struct prev_params *params = &prev->params;
> +	struct prev_params *params;
> +	unsigned long flags;
> +
> +	spin_lock_irqsave(&prev->params.lock, flags);
> +	params = (prev->params.active & OMAP3ISP_PREV_CONTRAST)
> +	       ? &prev->params.params[0] : &prev->params.params[1];

params = prev->params.params[!(prev->params.active & OMAP3ISP_PREV_CONTRAST)];

Same in contrast.

And shouldn't this be brightness here btw.?

?

>  	if (params->brightness != (brightness * ISPPRV_BRIGHT_UNITS)) {
>  		params->brightness = brightness * ISPPRV_BRIGHT_UNITS;
> -		prev->update |= OMAP3ISP_PREV_BRIGHTNESS;
> +		params->update |= OMAP3ISP_PREV_BRIGHTNESS;
>  	}
> +	spin_unlock_irqrestore(&prev->params.lock, flags);
>  }
>  
>  /*
> @@ -721,6 +733,75 @@ preview_config_yc_range(struct isp_prev_device *prev, const void *yclimit)
>  		       OMAP3_ISP_IOMEM_PREV, ISPPRV_SETUP_YC);
>  }
>  
> +static u32
> +preview_params_lock(struct isp_prev_device *prev, u32 update, bool shadow)
> +{
> +	u32 active = prev->params.active;
> +
> +	if (shadow) {
> +		/* Mark all shadow parameters we are going to touch as busy. */
> +		prev->params.params[0].busy |= ~active & update;
> +		prev->params.params[1].busy |= active & update;
> +	} else {
> +		/* Mark all active parameters we are going to touch as busy. */
> +		update = (prev->params.params[0].update & active)
> +		       | (prev->params.params[1].update & ~active);
> +
> +		prev->params.params[0].busy |= active & update;
> +		prev->params.params[1].busy |= ~active & update;
> +	}
> +
> +	return update;
> +}
> +
> +static void
> +preview_params_unlock(struct isp_prev_device *prev, u32 update, bool shadow)
> +{
> +	u32 active = prev->params.active;
> +
> +	if (shadow) {
> +		/* Set the update flag for shadow parameters that have been
> +		 * updated and clear the busy flag for all shadow parameters.
> +		 */
> +		prev->params.params[0].update |= (~active & update);
> +		prev->params.params[1].update |= (active & update);
> +		prev->params.params[0].busy &= active;
> +		prev->params.params[1].busy &= ~active;
> +	} else {
> +		/* Clear the update flag for active parameters that have been
> +		 * applied and the busy flag for all active parameters.
> +		 */
> +		prev->params.params[0].update &= ~(active & update);
> +		prev->params.params[1].update &= ~(~active & update);
> +		prev->params.params[0].busy &= ~active;
> +		prev->params.params[1].busy &= active;
> +	}
> +}
> +
> +static void preview_params_switch(struct isp_prev_device *prev)
> +{
> +	u32 to_switch;
> +
> +	/* Switch active parameters with updated shadow parameters when the
> +	 * shadow parameter has been updated and neither the active not the
> +	 * shadow parameter is busy.
> +	 */
> +	to_switch = (prev->params.params[0].update & ~prev->params.active)
> +		  | (prev->params.params[1].update & prev->params.active);
> +	to_switch &= ~(prev->params.params[0].busy |
> +		       prev->params.params[1].busy);
> +	if (to_switch == 0)
> +		return;
> +
> +	prev->params.active ^= to_switch;
> +
> +	/* Remove the update flag for the shadow copy of parameters we have
> +	 * switched.
> +	 */
> +	prev->params.params[0].update &= ~(~prev->params.active & to_switch);
> +	prev->params.params[1].update &= ~(prev->params.active & to_switch);
> +}
> +
>  /* preview parameters update structure */
>  struct preview_update {
>  	void (*config)(struct isp_prev_device *, const void *);
> @@ -834,37 +915,6 @@ static const struct preview_update update_attrs[] = {
>  };
>  
>  /*
> - * __preview_get_ptrs - helper function which return pointers to members
> - *                         of params and config structures.
> - * @params - pointer to preview_params structure.
> - * @param - return pointer to appropriate structure field.
> - * @configs - pointer to update config structure.
> - * @config - return pointer to appropriate structure field.
> - * @bit - for which feature to return pointers.
> - * Return size of corresponding prev_params member
> - */
> -static u32
> -__preview_get_ptrs(struct prev_params *params, void **param,
> -		   struct omap3isp_prev_update_config *configs,
> -		   void __user **config, unsigned int index)
> -{
> -	const struct preview_update *info = &update_attrs[index];
> -
> -	if (index >= ARRAY_SIZE(update_attrs)) {
> -		if (config)
> -			*config = NULL;
> -		*param = NULL;
> -		return 0;
> -	}
> -
> -	if (configs && config)
> -		*config = *(void **)((void *)configs + info->config_offset);
> -
> -	*param = (void *)params + info->param_offset;
> -	return info->param_size;
> -}
> -
> -/*
>   * preview_config - Copy and update local structure with userspace preview
>   *                  configuration.
>   * @prev: ISP preview engine
> @@ -876,36 +926,41 @@ __preview_get_ptrs(struct prev_params *params, void **param,
>  static int preview_config(struct isp_prev_device *prev,
>  			  struct omap3isp_prev_update_config *cfg)
>  {
> -	const struct preview_update *attr;
> -	struct prev_params *params;
> -	int i, bit, rval = 0;
> +	unsigned long flags;
> +	unsigned int i;
> +	int rval = 0;
> +	u32 update;
> +	u32 active;
>  
> -	params = &prev->params;
>  	if (cfg->update == 0)
>  		return 0;
>  
> -	if (prev->state != ISP_PIPELINE_STREAM_STOPPED) {
> -		unsigned long flags;
> +	/* Mark the shadow parameters we're going to update as busy. */
> +	spin_lock_irqsave(&prev->params.lock, flags);
> +	preview_params_lock(prev, cfg->update, true);
> +	active = prev->params.active;
> +	spin_unlock_irqrestore(&prev->params.lock, flags);
>  
> -		spin_lock_irqsave(&prev->lock, flags);
> -		prev->shadow_update = 1;
> -		spin_unlock_irqrestore(&prev->lock, flags);
> -	}
> +	update = 0;
>  
>  	for (i = 0; i < ARRAY_SIZE(update_attrs); i++) {
> -		attr = &update_attrs[i];
> -		bit = 1 << i;
> +		const struct preview_update *attr = &update_attrs[i];
> +		struct prev_params *params;
> +		unsigned int bit = 1 << i;
>  
>  		if (attr->skip || !(cfg->update & bit))
>  			continue;
>  
> +		params = &prev->params.params[!!(active & bit)];
> +
>  		if (cfg->flag & bit) {
> -			void *to = NULL, __user *from = NULL;
> -			unsigned long sz = 0;
> +			void __user *from = *(void * __user *)
> +				((void *)cfg + attr->config_offset);
> +			void *to = (void *)params + attr->param_offset;
> +			size_t size = attr->param_size;
>  
> -			sz = __preview_get_ptrs(params, &to, cfg, &from, i);
> -			if (to && from && sz) {
> -				if (copy_from_user(to, from, sz)) {
> +			if (to && from && size) {
> +				if (copy_from_user(to, from, size)) {
>  					rval = -EFAULT;
>  					break;
>  				}
> @@ -915,50 +970,59 @@ static int preview_config(struct isp_prev_device *prev,
>  			params->features &= ~bit;
>  		}
>  
> -		prev->update |= bit;
> +		update |= bit;
>  	}
>  
> -	prev->shadow_update = 0;
> +	spin_lock_irqsave(&prev->params.lock, flags);
> +	preview_params_unlock(prev, update, true);
> +	preview_params_switch(prev);
> +	spin_unlock_irqrestore(&prev->params.lock, flags);
> +
>  	return rval;
>  }
>  
>  /*
>   * preview_setup_hw - Setup preview registers and/or internal memory
>   * @prev: pointer to preview private structure
> + * @update: Bitmask of parameters to setup
> + * @active: Bitmask of parameters active in set 0
>   * Note: can be called from interrupt context
>   * Return none
>   */
> -static void preview_setup_hw(struct isp_prev_device *prev)
> +static void preview_setup_hw(struct isp_prev_device *prev, u32 update,
> +			     u32 active)
>  {
> -	struct prev_params *params = &prev->params;
> -	const struct preview_update *attr;
> -	unsigned int bit;
>  	unsigned int i;
> -	void *param_ptr;
> +	u32 features;
>  
> -	if (prev->update == 0)
> +	if (update == 0)
>  		return;
>  
> +	features = (prev->params.params[0].features & active)
> +		 | (prev->params.params[1].features & ~active);
> +
>  	for (i = 0; i < ARRAY_SIZE(update_attrs); i++) {
> -		attr = &update_attrs[i];
> -		bit = 1 << i;
> +		const struct preview_update *attr = &update_attrs[i];
> +		struct prev_params *params;
> +		unsigned int bit = 1 << i;
> +		void *param_ptr;
>  
> -		if (!(prev->update & bit))
> +		if (!(update & bit))
>  			continue;
>  
> +		params = &prev->params.params[!(active & bit)];
> +
>  		if (params->features & bit) {
>  			if (attr->config) {
> -				__preview_get_ptrs(params, &param_ptr, NULL,
> -						   NULL, i);
> +				param_ptr = (void *)params + attr->param_offset;
>  				attr->config(prev, param_ptr);
>  			}
>  			if (attr->enable)
>  				attr->enable(prev, 1);
> -		} else
> +		} else {
>  			if (attr->enable)
>  				attr->enable(prev, 0);
> -
> -		prev->update &= ~bit;
> +		}
>  	}
>  }
>  
> @@ -996,13 +1060,17 @@ preview_config_ycpos(struct isp_prev_device *prev,
>  static void preview_config_averager(struct isp_prev_device *prev, u8 average)
>  {
>  	struct isp_device *isp = to_isp_device(prev);
> +	struct prev_params *params;
>  	int reg = 0;
>  
> -	if (prev->params.cfa.format == OMAP3ISP_CFAFMT_BAYER)
> +	params = (prev->params.active & OMAP3ISP_PREV_CFA)
> +	       ? &prev->params.params[0] : &prev->params.params[1];



> +	if (params->cfa.format == OMAP3ISP_CFAFMT_BAYER)
>  		reg = ISPPRV_AVE_EVENDIST_2 << ISPPRV_AVE_EVENDIST_SHIFT |
>  		      ISPPRV_AVE_ODDDIST_2 << ISPPRV_AVE_ODDDIST_SHIFT |
>  		      average;
> -	else if (prev->params.cfa.format == OMAP3ISP_CFAFMT_RGBFOVEON)
> +	else if (params->cfa.format == OMAP3ISP_CFAFMT_RGBFOVEON)
>  		reg = ISPPRV_AVE_EVENDIST_3 << ISPPRV_AVE_EVENDIST_SHIFT |
>  		      ISPPRV_AVE_ODDDIST_3 << ISPPRV_AVE_ODDDIST_SHIFT |
>  		      average;
> @@ -1020,33 +1088,35 @@ static void preview_config_averager(struct isp_prev_device *prev, u8 average)
>   *
>   * See the explanation at the PREV_MARGIN_* definitions for more details.
>   */
> -static void preview_config_input_size(struct isp_prev_device *prev)
> +static void preview_config_input_size(struct isp_prev_device *prev, u32 active)
>  {
>  	struct isp_device *isp = to_isp_device(prev);
> -	struct prev_params *params = &prev->params;
>  	unsigned int sph = prev->crop.left;
>  	unsigned int eph = prev->crop.left + prev->crop.width - 1;
>  	unsigned int slv = prev->crop.top;
>  	unsigned int elv = prev->crop.top + prev->crop.height - 1;
> +	u32 features;
>  
> -	if (params->features & OMAP3ISP_PREV_CFA) {
> +	features = (prev->params.params[0].features & active)
> +		 | (prev->params.params[1].features & ~active);
> +
> +	if (features & OMAP3ISP_PREV_CFA) {
>  		sph -= 2;
>  		eph += 2;
>  		slv -= 2;
>  		elv += 2;
>  	}
> -	if (params->features & (OMAP3ISP_PREV_DEFECT_COR | OMAP3ISP_PREV_NF)) {
> +	if (features & (OMAP3ISP_PREV_DEFECT_COR | OMAP3ISP_PREV_NF)) {
>  		sph -= 2;
>  		eph += 2;
>  		slv -= 2;
>  		elv += 2;
>  	}
> -	if (params->features & OMAP3ISP_PREV_HRZ_MED) {
> +	if (features & OMAP3ISP_PREV_HRZ_MED) {
>  		sph -= 2;
>  		eph += 2;
>  	}
> -	if (params->features & (OMAP3ISP_PREV_CHROMA_SUPP |
> -				OMAP3ISP_PREV_LUMAENH))
> +	if (features & (OMAP3ISP_PREV_CHROMA_SUPP | OMAP3ISP_PREV_LUMAENH))
>  		sph -= 2;
>  
>  	isp_reg_writel(isp, (sph << ISPPRV_HORZ_INFO_SPH_SHIFT) | eph,
> @@ -1181,8 +1251,16 @@ int omap3isp_preview_busy(struct isp_prev_device *prev)
>   */
>  void omap3isp_preview_restore_context(struct isp_device *isp)
>  {
> -	isp->isp_prev.update = OMAP3ISP_PREV_FEATURES_END - 1;
> -	preview_setup_hw(&isp->isp_prev);
> +	struct isp_prev_device *prev = &isp->isp_prev;
> +	const u32 update = OMAP3ISP_PREV_FEATURES_END - 1;
> +
> +	prev->params.params[0].update = prev->params.active & update;
> +	prev->params.params[1].update = ~prev->params.active & update;
> +
> +	preview_setup_hw(prev, update, prev->params.active);
> +
> +	prev->params.params[0].update = 0;
> +	prev->params.params[1].update = 0;
>  }
>  
>  /*
> @@ -1241,12 +1319,21 @@ static void preview_print_status(struct isp_prev_device *prev)
>  /*
>   * preview_init_params - init image processing parameters.
>   * @prev: pointer to previewer private structure
> - * return none
>   */
>  static void preview_init_params(struct isp_prev_device *prev)
>  {
> -	struct prev_params *params = &prev->params;
> -	int i = 0;
> +	struct prev_params *params;
> +	unsigned int i;
> +
> +	spin_lock_init(&prev->params.lock);
> +
> +	prev->params.active = ~0;
> +	prev->params.params[0].busy = 0;
> +	prev->params.params[0].update = OMAP3ISP_PREV_FEATURES_END - 1;
> +	prev->params.params[1].busy = 0;
> +	prev->params.params[1].update = 0;
> +
> +	params = &prev->params.params[0];
>  
>  	/* Init values */
>  	params->contrast = ISPPRV_CONTRAST_DEF * ISPPRV_CONTRAST_UNITS;
> @@ -1290,8 +1377,6 @@ static void preview_init_params(struct isp_prev_device *prev)
>  			 | OMAP3ISP_PREV_RGB2RGB | OMAP3ISP_PREV_COLOR_CONV
>  			 | OMAP3ISP_PREV_WB | OMAP3ISP_PREV_BRIGHTNESS
>  			 | OMAP3ISP_PREV_CONTRAST;
> -
> -	prev->update = OMAP3ISP_PREV_FEATURES_END - 1;
>  }
>  
>  /*
> @@ -1320,8 +1405,17 @@ static void preview_configure(struct isp_prev_device *prev)
>  {
>  	struct isp_device *isp = to_isp_device(prev);
>  	struct v4l2_mbus_framefmt *format;
> +	unsigned long flags;
> +	u32 update;
> +	u32 active;
>  
> -	preview_setup_hw(prev);
> +	spin_lock_irqsave(&prev->params.lock, flags);
> +	/* Mark all active parameters we are going to touch as busy. */
> +	update = preview_params_lock(prev, 0, false);
> +	active = prev->params.active;
> +	spin_unlock_irqrestore(&prev->params.lock, flags);
> +
> +	preview_setup_hw(prev, update, active);
>  
>  	if (prev->output & PREVIEW_OUTPUT_MEMORY)
>  		isp_reg_set(isp, OMAP3_ISP_IOMEM_PREV, ISPPRV_PCR,
> @@ -1342,7 +1436,7 @@ static void preview_configure(struct isp_prev_device *prev)
>  
>  	preview_adjust_bandwidth(prev);
>  
> -	preview_config_input_size(prev);
> +	preview_config_input_size(prev, active);
>  
>  	if (prev->input == PREVIEW_INPUT_CCDC)
>  		preview_config_inlineoffset(prev, 0);
> @@ -1359,6 +1453,10 @@ static void preview_configure(struct isp_prev_device *prev)
>  
>  	preview_config_averager(prev, 0);
>  	preview_config_ycpos(prev, format->code);
> +
> +	spin_lock_irqsave(&prev->params.lock, flags);
> +	preview_params_unlock(prev, update, false);
> +	spin_unlock_irqrestore(&prev->params.lock, flags);
>  }
>  
>  /* -----------------------------------------------------------------------------
> @@ -1447,25 +1545,30 @@ static void preview_isr_buffer(struct isp_prev_device *prev)
>  void omap3isp_preview_isr(struct isp_prev_device *prev)
>  {
>  	unsigned long flags;
> +	u32 update;
> +	u32 active;
>  
>  	if (omap3isp_module_sync_is_stopping(&prev->wait, &prev->stopping))
>  		return;
>  
> -	spin_lock_irqsave(&prev->lock, flags);
> -	if (prev->shadow_update)
> -		goto done;
> +	spin_lock_irqsave(&prev->params.lock, flags);
> +	preview_params_switch(prev);
> +	update = preview_params_lock(prev, 0, false);
> +	active = prev->params.active;
> +	spin_unlock_irqrestore(&prev->params.lock, flags);
>  
> -	preview_setup_hw(prev);
> -	preview_config_input_size(prev);
> -
> -done:
> -	spin_unlock_irqrestore(&prev->lock, flags);
> +	preview_setup_hw(prev, update, active);
> +	preview_config_input_size(prev, active);
>  
>  	if (prev->input == PREVIEW_INPUT_MEMORY ||
>  	    prev->output & PREVIEW_OUTPUT_MEMORY)
>  		preview_isr_buffer(prev);
>  	else if (prev->state == ISP_PIPELINE_STREAM_CONTINUOUS)
>  		preview_enable_oneshot(prev);
> +
> +	spin_lock_irqsave(&prev->params.lock, flags);
> +	preview_params_unlock(prev, update, false);
> +	spin_unlock_irqrestore(&prev->params.lock, flags);
>  }
>  
>  /* -----------------------------------------------------------------------------
> @@ -1551,7 +1654,6 @@ static int preview_set_stream(struct v4l2_subdev *sd, int enable)
>  	struct isp_video *video_out = &prev->video_out;
>  	struct isp_device *isp = to_isp_device(prev);
>  	struct device *dev = to_device(prev);
> -	unsigned long flags;
>  
>  	if (prev->state == ISP_PIPELINE_STREAM_STOPPED) {
>  		if (enable == ISP_PIPELINE_STREAM_STOPPED)
> @@ -1588,11 +1690,9 @@ static int preview_set_stream(struct v4l2_subdev *sd, int enable)
>  		if (omap3isp_module_sync_idle(&sd->entity, &prev->wait,
>  					      &prev->stopping))
>  			dev_dbg(dev, "%s: stop timeout.\n", sd->name);
> -		spin_lock_irqsave(&prev->lock, flags);
>  		omap3isp_sbl_disable(isp, OMAP3_ISP_SBL_PREVIEW_READ);
>  		omap3isp_sbl_disable(isp, OMAP3_ISP_SBL_PREVIEW_WRITE);
>  		omap3isp_subclk_disable(isp, OMAP3_ISP_SUBCLK_PREVIEW);
> -		spin_unlock_irqrestore(&prev->lock, flags);
>  		isp_video_dmaqueue_flags_clr(video_out);
>  		break;
>  	}
> @@ -2200,7 +2300,7 @@ error_video_in:
>  }
>  
>  /*
> - * isp_preview_init - Previewer initialization.
> + * omap3isp_preview_init - Previewer initialization.
>   * @dev : Pointer to ISP device
>   * return -ENOMEM or zero on success
>   */
> @@ -2208,8 +2308,8 @@ int omap3isp_preview_init(struct isp_device *isp)
>  {
>  	struct isp_prev_device *prev = &isp->isp_prev;
>  
> -	spin_lock_init(&prev->lock);
>  	init_waitqueue_head(&prev->wait);
> +
>  	preview_init_params(prev);
>  
>  	return preview_init_entities(prev);
> diff --git a/drivers/media/video/omap3isp/isppreview.h b/drivers/media/video/omap3isp/isppreview.h
> index 6ee8306..6663ab6 100644
> --- a/drivers/media/video/omap3isp/isppreview.h
> +++ b/drivers/media/video/omap3isp/isppreview.h
> @@ -69,6 +69,8 @@ enum preview_ycpos_mode {
>  
>  /*
>   * struct prev_params - Structure for all configuration
> + * @busy: Bitmask of busy parameters (being updated or used)
> + * @update: Bitmask of the parameters to be updated
>   * @features: Set of features enabled.
>   * @cfa: CFA coefficients.
>   * @csup: Chroma suppression coefficients.
> @@ -86,6 +88,8 @@ enum preview_ycpos_mode {
>   * @brightness: Brightness.
>   */
>  struct prev_params {
> +	u32 busy;
> +	u32 update;
>  	u32 features;
>  	struct omap3isp_prev_cfa cfa;
>  	struct omap3isp_prev_csup csup;
> @@ -118,12 +122,11 @@ struct prev_params {
>   * @output: Bitmask of the active output
>   * @video_in: Input video entity
>   * @video_out: Output video entity
> - * @params: Module configuration data
> - * @shadow_update: If set, update the hardware configured in the next interrupt
> + * @params.params : Active and shadow parameters sets
> + * @params.active: Bitmask of parameters active in set 0
> + * @params.lock: Parameters lock, protects params.active and params.shadow
>   * @underrun: Whether the preview entity has queued buffers on the output
>   * @state: Current preview pipeline state
> - * @lock: Shadow update lock
> - * @update: Bitmask of the parameters to be updated
>   *
>   * This structure is used to store the OMAP ISP Preview module Information.
>   */
> @@ -140,13 +143,15 @@ struct isp_prev_device {
>  	struct isp_video video_in;
>  	struct isp_video video_out;
>  
> -	struct prev_params params;
> -	unsigned int shadow_update:1;
> +	struct {
> +		struct prev_params params[2];
> +		u32 active;
> +		spinlock_t lock;
> +	} params;
> +
>  	enum isp_pipeline_stream_state state;
>  	wait_queue_head_t wait;
>  	atomic_t stopping;
> -	spinlock_t lock;
> -	u32 update;
>  };
>  
>  struct isp_device;
> -- 
> 1.7.3.4
> 

Cheers,

-- 
Sakari Ailus
e-mail: sakari.ailus@iki.fi	jabber/XMPP/Gmail: sailus@retiisi.org.uk