[PATCH] drm/i915: Increase I915_PARAM_MMAP_GTT_VERSION version to indicate support for partial mmaps

[Nirmoy Das]

On 3/6/2025 10:08 PM, José Roberto de Souza wrote:
> Commit 255fc1703e42 ("drm/i915/gem: Calculate object page offset for partial memory mapping")
> was the last patch of several patches fixing multiple partial mmaps.
> But without a bump in I915_PARAM_MMAP_GTT_VERSION there is no clean
> way for UMD to know if it can do multiple partial mmaps.
>
> Fixes: 255fc1703e42 ("drm/i915/gem: Calculate object page offset for partial memory mapping")
> Cc: Andi Shyti <andi.shyti at linux.intel.com>
> Cc: Nirmoy Das <nirmoy.das at intel.com>
> Cc: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Reviewed-by: Nirmoy Das <nirmoy.das at intel.com>
> Signed-off-by: José Roberto de Souza <jose.souza at intel.com>
> ---
>  drivers/gpu/drm/i915/gem/i915_gem_mman.c | 5 ++++-
>  1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/gem/i915_gem_mman.c b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> index 21274aa9bdddc..c3dabb8579605 100644
> --- a/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> +++ b/drivers/gpu/drm/i915/gem/i915_gem_mman.c
> @@ -164,6 +164,9 @@ static unsigned int tile_row_pages(const struct drm_i915_gem_object *obj)
>   * 4 - Support multiple fault handlers per object depending on object's
>   *     backing storage (a.k.a. MMAP_OFFSET).
>   *
> + * 5 - Support multiple partial mmaps(mmap part of BO + unmap a offset, multiple
> + *     times with different size and offset).
> + *
>   * Restrictions:
>   *
>   *  * snoopable objects cannot be accessed via the GTT. It can cause machine
> @@ -191,7 +194,7 @@ static unsigned int tile_row_pages(const struct drm_i915_gem_object *obj)
>   */
>  int i915_gem_mmap_gtt_version(void)
>  {
> -	return 4;
> +	return 5;
>  }
>  
>  static inline struct i915_gtt_view