Re: [PATCH] drm/i915: Align initial plane backing objects correctly

[Jani Nikula <jani.nikula@linux.intel.com>]

On Wed, 11 Feb 2015, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> Some bios really like to joke and start the planes at an offset ...
> hooray!
>
> Align start and end to fix this.
>
> v2: Fixup calculation of size, spotted by Chris Wilson.
>
> v3: Fix serious fumble I've just spotted.
>
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=86883
> Cc: stable@vger.kernel.org
> Cc: Johannes W <jargon@molb.org>
> Cc: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Reported-by: Johannes W <jargon@molb.org>
> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>

Tested-by: Johannes W <jargon@molb.org>

>
> --
>
> Johannes, can you please test this patch instead of the one from
> Chris?
>
> Thanks, Daniel
> ---
>  drivers/gpu/drm/i915/i915_gem_stolen.c |  5 +----
>  drivers/gpu/drm/i915/intel_display.c   | 18 ++++++++++++------
>  2 files changed, 13 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_stolen.c b/drivers/gpu/drm/i915/i915_gem_stolen.c
> index 59401f3b902c..4382696087c9 100644
> --- a/drivers/gpu/drm/i915/i915_gem_stolen.c
> +++ b/drivers/gpu/drm/i915/i915_gem_stolen.c
> @@ -485,10 +485,7 @@ i915_gem_object_create_stolen_for_preallocated(struct drm_device *dev,
>  			stolen_offset, gtt_offset, size);
>  
>  	/* KISS and expect everything to be page-aligned */
> -	BUG_ON(stolen_offset & 4095);
> -	BUG_ON(size & 4095);
> -
> -	if (WARN_ON(size == 0))
> +	if (WARN_ON(size == 0 || stolen_offset & 4095 || size & 4095))
>  		return NULL;
>  
>  	stolen = kzalloc(sizeof(*stolen), GFP_KERNEL);
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 2655b63d65e9..fc855b9548ec 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -2372,13 +2372,19 @@ intel_alloc_plane_obj(struct intel_crtc *crtc,
>  	struct drm_i915_gem_object *obj = NULL;
>  	struct drm_mode_fb_cmd2 mode_cmd = { 0 };
>  	struct drm_framebuffer *fb = &plane_config->fb->base;
> -	u32 base = plane_config->base;
> +	u32 base_aligned = round_down(plane_config->base, PAGE_SIZE);
> +	u32 size_aligned = round_up(plane_config->base + plane_config->size,
> +				    PAGE_SIZE);
> +
> +	size_aligned -= base_aligned;
>  
>  	if (plane_config->size == 0)
>  		return false;
>  
> -	obj = i915_gem_object_create_stolen_for_preallocated(dev, base, base,
> -							     plane_config->size);
> +	obj = i915_gem_object_create_stolen_for_preallocated(dev,
> +							     base_aligned,
> +							     base_aligned,
> +							     size_aligned);
>  	if (!obj)
>  		return false;
>  
> @@ -6654,7 +6660,7 @@ i9xx_get_initial_plane_config(struct intel_crtc *crtc,
>  	aligned_height = intel_fb_align_height(dev, fb->height,
>  					       plane_config->tiling);
>  
> -	plane_config->size = PAGE_ALIGN(fb->pitches[0] * aligned_height);
> +	plane_config->size = fb->pitches[0] * aligned_height;
>  
>  	DRM_DEBUG_KMS("pipe/plane %c/%d with fb: size=%dx%d@%d, offset=%x, pitch %d, size 0x%x\n",
>  		      pipe_name(pipe), plane, fb->width, fb->height,
> @@ -7694,7 +7700,7 @@ skylake_get_initial_plane_config(struct intel_crtc *crtc,
>  	aligned_height = intel_fb_align_height(dev, fb->height,
>  					       plane_config->tiling);
>  
> -	plane_config->size = ALIGN(fb->pitches[0] * aligned_height, PAGE_SIZE);
> +	plane_config->size = fb->pitches[0] * aligned_height;
>  
>  	DRM_DEBUG_KMS("pipe %c with fb: size=%dx%d@%d, offset=%x, pitch %d, size 0x%x\n",
>  		      pipe_name(pipe), fb->width, fb->height,
> @@ -7787,7 +7793,7 @@ ironlake_get_initial_plane_config(struct intel_crtc *crtc,
>  	aligned_height = intel_fb_align_height(dev, fb->height,
>  					       plane_config->tiling);
>  
> -	plane_config->size = PAGE_ALIGN(fb->pitches[0] * aligned_height);
> +	plane_config->size = fb->pitches[0] * aligned_height;
>  
>  	DRM_DEBUG_KMS("pipe %c with fb: size=%dx%d@%d, offset=%x, pitch %d, size 0x%x\n",
>  		      pipe_name(pipe), fb->width, fb->height,
> -- 
> 2.1.4
>

-- 
Jani Nikula, Intel Open Source Technology Center