Re: [PATCH] drm/i915: Introduce FBC False Color for debug purposes.

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

On Mon, Jul 07, 2014 at 11:42:04AM -0700, Rodrigo Vivi wrote:
> With this bit enabled, HW changes the color when compressing frames for
> debug purposes.
> 
> ALthough the simple way to enable a single bit is over intel_reg_write,
> this value is overwriten on next update_fbc so depending on the workload
> it is not possible to set this bit with intel-gpu-tools. So this patch
> introduces a persistent way to enable false color over debugfs.
> 
> v2: Use DEFINE_SIMPLE_ATTRIBUTE as Daniel suggested
> 
> Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
> Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
> ---
>  drivers/gpu/drm/i915/i915_debugfs.c | 42 +++++++++++++++++++++++++++++++++++++
>  drivers/gpu/drm/i915/i915_drv.h     |  2 ++
>  drivers/gpu/drm/i915/i915_reg.h     |  1 +
>  drivers/gpu/drm/i915/intel_pm.c     |  6 ++++++
>  4 files changed, 51 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> index c1b88a8..b049fc5 100644
> --- a/drivers/gpu/drm/i915/i915_debugfs.c
> +++ b/drivers/gpu/drm/i915/i915_debugfs.c
> @@ -1510,6 +1510,47 @@ static int i915_fbc_status(struct seq_file *m, void *unused)
>  	return 0;
>  }
>  
> +static int i915_fbc_fc_get(void *data, u64 *val)
> +{
> +	struct drm_device *dev = data;
> +	struct drm_i915_private *dev_priv = dev->dev_private;
> +
> +	if (INTEL_INFO(dev)->gen < 5)
> +		return -ENODEV;

Did you test this on ILK/SNB? Bspec says the bit is MBZ before IVB.

-- 
Ville Syrjälä
Intel OTC