Re: [RFC 5/6] drm/i915: Allow fb modifier to set framebuffer tiling

Daniel Vetter
2015-02-02T09:53:08Z

On Fri, Jan 30, 2015 at 05:36:57PM +0000, Tvrtko Ursulin wrote:
> From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
>
> Use the fb modifier if it was specified over object tiling mode.
>
> Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> ---
> drivers/gpu/drm/i915/intel_display.c | 40 +++++++++++++++++++++++++++++-------
> 1 file changed, 33 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index e22afbe..ca69da0 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -12671,6 +12671,20 @@ static const struct drm_framebuffer_funcs intel_fb_funcs = {
> .create_handle = intel_user_framebuffer_create_handle,
> };
>
> +static unsigned int
> +intel_fb_modifier_to_tiling(u64 modifier)
> +{
> + switch (modifier) {
> + case I915_FORMAT_MOD_X_TILED:
> + return I915_TILING_X;
> + default:
> + case I915_FORMAT_MOD_NONE:
> + break;
> + }
> +
> + return I915_TILING_NONE;
> +}
> +
> static int intel_framebuffer_init(struct drm_device *dev,
> struct intel_framebuffer *intel_fb,
> struct drm_mode_fb_cmd2 *mode_cmd,
> @@ -12678,11 +12692,23 @@ static int intel_framebuffer_init(struct drm_device *dev,
> {
> int aligned_height;
> int pitch_limit;
> + unsigned int tiling_mode = obj->tiling_mode;
> int ret;
>
> WARN_ON(!mutex_is_locked(&dev->struct_mutex));
>
> - if (obj->tiling_mode == I915_TILING_Y) {
> + if (mode_cmd->flags & DRM_MODE_FB_MODIFIERS) {
> + tiling_mode =
> + intel_fb_modifier_to_tiling(mode_cmd->modifier[0]);
> + if (tiling_mode != obj->tiling_mode &&
> + obj->tiling_mode != I915_TILING_NONE) {
> + DRM_ERROR("Tiling modifier mismatch %u vs obj %u!\n",
> + tiling_mode, obj->tiling_mode);
> + return -EINVAL;
> + }
> + }

Ah, here comes the magic. I think this might be simpler if we just use
->modifier (and fix it up if FB_MODIFIERS isn't set).

Btw another reason for this split is that this way we have a clear
separation between the tiling modes supported generally (as fb modifiers)
and the tiling modes supported by fences. It might therefore make sense to
rename obj->tiling_mode with a cocci patch to obj->fencing_mode or
->fence_tiling_mode). To make it really clear that it's just about the
global gtt fences and nothing more.
-Daniel

> +
> + if (tiling_mode == I915_TILING_Y) {
> DRM_DEBUG("hardware does not support tiling Y\n");
> return -EINVAL;
> }
> @@ -12696,12 +12722,12 @@ static int intel_framebuffer_init(struct drm_device *dev,
> if (INTEL_INFO(dev)->gen >= 5 && !IS_VALLEYVIEW(dev)) {
> pitch_limit = 32*1024;
> } else if (INTEL_INFO(dev)->gen >= 4) {
> - if (obj->tiling_mode)
> + if (tiling_mode)
> pitch_limit = 16*1024;
> else
> pitch_limit = 32*1024;
> } else if (INTEL_INFO(dev)->gen >= 3) {
> - if (obj->tiling_mode)
> + if (tiling_mode)
> pitch_limit = 8*1024;
> else
> pitch_limit = 16*1024;
> @@ -12711,12 +12737,12 @@ static int intel_framebuffer_init(struct drm_device *dev,
>
> if (mode_cmd->pitches[0] > pitch_limit) {
> DRM_DEBUG("%s pitch (%d) must be at less than %d\n",
> - obj->tiling_mode ? "tiled" : "linear",
> + tiling_mode ? "tiled" : "linear",
> mode_cmd->pitches[0], pitch_limit);
> return -EINVAL;
> }
>
> - if (obj->tiling_mode != I915_TILING_NONE &&
> + if (tiling_mode != I915_TILING_NONE && obj->stride &&
> mode_cmd->pitches[0] != obj->stride) {
> DRM_DEBUG("pitch (%d) must match tiling stride (%d)\n",
> mode_cmd->pitches[0], obj->stride);
> @@ -12771,7 +12797,7 @@ static int intel_framebuffer_init(struct drm_device *dev,
> return -EINVAL;
>
> aligned_height = intel_fb_align_height(dev, mode_cmd->height,
> - obj->tiling_mode);
> + tiling_mode);
> /* FIXME drm helper for size checks (especially planar formats)? */
> if (obj->base.size < aligned_height * mode_cmd->pitches[0])
> return -EINVAL;
> @@ -12779,7 +12805,7 @@ static int intel_framebuffer_init(struct drm_device *dev,
> drm_helper_mode_fill_fb_struct(&intel_fb->base, mode_cmd);
> intel_fb->obj = obj;
> intel_fb->obj->framebuffer_references++;
> - intel_fb->tiling_mode = obj->tiling_mode;
> + intel_fb->tiling_mode = tiling_mode;
>
> ret = drm_framebuffer_init(dev, &intel_fb->base, &intel_fb_funcs);
> if (ret) {
> --
> 2.2.2
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch