[Intel-gfx] [PATCH] drm/i915: Check the minimum pitch for the user framebuffer

[Daniel Vetter]

On Tue, Jun 10, 2014 at 10:22:33PM +0100, Chris Wilson wrote:
> Compute the smallest pitch required for a linear framebuffer and assert
> that the user has declared a pitch that meets that minimum requirement.
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index cc62b140eb1c..ef34badbe69c 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -11808,6 +11808,8 @@ static int intel_framebuffer_init(struct drm_device *dev,
>  {
>  	int aligned_height;
>  	int pitch_limit;
> +	int depth;
> +	int bpp;
>  	int ret;
>  
>  	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
> @@ -11823,6 +11825,15 @@ static int intel_framebuffer_init(struct drm_device *dev,
>  		return -EINVAL;
>  	}
>  
> +	drm_fb_get_bpp_depth(mode_cmd->pixel_format, &bpp, &depth);
> +	if (mode_cmd->pitches[0] < intel_framebuffer_pitch_for_width(mode_cmd->width,
> +								     bpp)) {

Won't this foul up universal planes? Iirc we have a minimal pitch of 128b
somewhere, but cursors are happy with 64. Also not sure about
overlays/planes.

If this blows up I guess we need to patch up the setplane/cursor functions
correctly.
-Daniel

> +		DRM_DEBUG("pitch (%d) must be at least the linear stride (%d)\n",
> +			  mode_cmd->pitches[0],
> +			  intel_framebuffer_pitch_for_width(mode_cmd->width, bpp));
> +		return -EINVAL;
> +	}
> +
>  	if (INTEL_INFO(dev)->gen >= 5 && !IS_VALLEYVIEW(dev)) {
>  		pitch_limit = 32*1024;
>  	} else if (INTEL_INFO(dev)->gen >= 4) {
> -- 
> 2.0.0
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch