[PATCH v2 13/15] drm/i915/fbdev: Fix smem_start for LMEMBAR stolen objects

[Andrzej Hajda]

On 15.12.2023 11:59, Ville Syrjala wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> The "io" address of an object is its dma address minus the
> region.start. Subtract the latter to make smem_start correct.
> The current code happens to work for genuine LMEM objects
> as LMEM region.start==0, but for LMEMBAR stolen objects
> region.start!=0.
> 
> TODO: perhaps just set smem_start=0 always as our .fb_mmap()
> implementation no longer depends on it? Need to double check
> it's not needed for anything else...
> 
> Cc: Paz Zcharya <pazz at chromium.org>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>

Reviewed-by: Andrzej Hajda <andrzej.hajda at intel.com>

Regards
Andrzej

> ---
>   drivers/gpu/drm/i915/display/intel_fbdev_fb.c | 3 ++-
>   1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/display/intel_fbdev_fb.c b/drivers/gpu/drm/i915/display/intel_fbdev_fb.c
> index 1ac05d90b2e8..0665f943f65f 100644
> --- a/drivers/gpu/drm/i915/display/intel_fbdev_fb.c
> +++ b/drivers/gpu/drm/i915/display/intel_fbdev_fb.c
> @@ -79,7 +79,8 @@ int intel_fbdev_fb_fill_info(struct drm_i915_private *i915, struct fb_info *info
>   		/* Use fbdev's framebuffer from lmem for discrete */
>   		info->fix.smem_start =
>   			(unsigned long)(mem->io.start +
> -					i915_gem_object_get_dma_address(obj, 0));
> +					i915_gem_object_get_dma_address(obj, 0) -
> +					mem->region.start);
>   		info->fix.smem_len = obj->base.size;
>   	} else {
>   		struct i915_ggtt *ggtt = to_gt(i915)->ggtt;