Re: [PATCH v5 03/14] drm/fb-helper: separate the fb_setcmap helper into atomic and legacy paths

[Daniel Vetter]

On Thu, Jul 13, 2017 at 06:25:27PM +0200, Peter Rosin wrote:
> The legacy path implements setcmap in terms of crtc .gamma_set.
> 
> The atomic path implements setcmap by directly updating the crtc gamma_lut
> property.
> 
> This has a couple of benefits:
> - it makes the redundant fb helpers .load_lut, .gamma_set and .gamma_get
>   completely obsolete. They are now unused and subject for removal.
> - atomic drivers that support clut modes get fbdev support for those from
>   the drm core. This includes atmel-hlcdc, but perhaps others as well?
> 
> Signed-off-by: Peter Rosin <peda@xxxxxxxxxx>

Ok, I merged the core parts. I'll wait with the driver stuff for a bit
more (maybe 1-2 weeks) for more acks. Pls remind me in case I forget to
pull them in.

Thanks a lot for doing this, great work!
-Daniel
> ---
>  drivers/gpu/drm/drm_fb_helper.c | 231 ++++++++++++++++++++++++++++------------
>  1 file changed, 160 insertions(+), 71 deletions(-)
> 
> diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
> index 721511da4de6..42090fe00ef9 100644
> --- a/drivers/gpu/drm/drm_fb_helper.c
> +++ b/drivers/gpu/drm/drm_fb_helper.c
> @@ -1195,27 +1195,6 @@ void drm_fb_helper_set_suspend_unlocked(struct drm_fb_helper *fb_helper,
>  }
>  EXPORT_SYMBOL(drm_fb_helper_set_suspend_unlocked);
>  
> -static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green,
> -		     u16 blue, u16 regno, struct fb_info *info)
> -{
> -	struct drm_fb_helper *fb_helper = info->par;
> -	struct drm_framebuffer *fb = fb_helper->fb;
> -
> -	/*
> -	 * The driver really shouldn't advertise pseudo/directcolor
> -	 * visuals if it can't deal with the palette.
> -	 */
> -	if (WARN_ON(!fb_helper->funcs->gamma_set ||
> -		    !fb_helper->funcs->gamma_get))
> -		return -EINVAL;
> -
> -	WARN_ON(fb->format->cpp[0] != 1);
> -
> -	fb_helper->funcs->gamma_set(crtc, red, green, blue, regno);
> -
> -	return 0;
> -}
> -
>  static int setcmap_pseudo_palette(struct fb_cmap *cmap, struct fb_info *info)
>  {
>  	u32 *palette = (u32 *)info->pseudo_palette;
> @@ -1248,57 +1227,138 @@ static int setcmap_pseudo_palette(struct fb_cmap *cmap, struct fb_info *info)
>  	return 0;
>  }
>  
> -/**
> - * drm_fb_helper_setcmap - implementation for &fb_ops.fb_setcmap
> - * @cmap: cmap to set
> - * @info: fbdev registered by the helper
> - */
> -int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
> +static int setcmap_legacy(struct fb_cmap *cmap, struct fb_info *info)
>  {
>  	struct drm_fb_helper *fb_helper = info->par;
> -	struct drm_device *dev = fb_helper->dev;
> -	const struct drm_crtc_helper_funcs *crtc_funcs;
> -	u16 *red, *green, *blue, *transp;
>  	struct drm_crtc *crtc;
>  	u16 *r, *g, *b;
> -	int i, j, rc = 0;
> -	int start;
> +	int i, ret = 0;
>  
> -	if (oops_in_progress)
> -		return -EBUSY;
> +	drm_modeset_lock_all(fb_helper->dev);
> +	for (i = 0; i < fb_helper->crtc_count; i++) {
> +		crtc = fb_helper->crtc_info[i].mode_set.crtc;
> +		if (!crtc->funcs->gamma_set || !crtc->gamma_size)
> +			return -EINVAL;
>  
> -	mutex_lock(&fb_helper->lock);
> -	if (!drm_fb_helper_is_bound(fb_helper)) {
> -		mutex_unlock(&fb_helper->lock);
> -		return -EBUSY;
> +		if (cmap->start + cmap->len > crtc->gamma_size)
> +			return -EINVAL;
> +
> +		r = crtc->gamma_store;
> +		g = r + crtc->gamma_size;
> +		b = g + crtc->gamma_size;
> +
> +		memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(*r));
> +		memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(*g));
> +		memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(*b));
> +
> +		ret = crtc->funcs->gamma_set(crtc, r, g, b,
> +					     crtc->gamma_size, NULL);
> +		if (ret)
> +			return ret;
>  	}
> +	drm_modeset_unlock_all(fb_helper->dev);
>  
> -	drm_modeset_lock_all(dev);
> -	if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
> -		rc = setcmap_pseudo_palette(cmap, info);
> -		goto out;
> +	return ret;
> +}
> +
> +static struct drm_property_blob *setcmap_new_gamma_lut(struct drm_crtc *crtc,
> +						       struct fb_cmap *cmap)
> +{
> +	struct drm_device *dev = crtc->dev;
> +	struct drm_property_blob *gamma_lut;
> +	struct drm_color_lut *lut;
> +	int size = crtc->gamma_size;
> +	int i;
> +
> +	if (!size || cmap->start + cmap->len > size)
> +		return ERR_PTR(-EINVAL);
> +
> +	gamma_lut = drm_property_create_blob(dev, sizeof(*lut) * size, NULL);
> +	if (IS_ERR(gamma_lut))
> +		return gamma_lut;
> +
> +	lut = (struct drm_color_lut *)gamma_lut->data;
> +	if (cmap->start || cmap->len != size) {
> +		u16 *r = crtc->gamma_store;
> +		u16 *g = r + crtc->gamma_size;
> +		u16 *b = g + crtc->gamma_size;
> +
> +		for (i = 0; i < cmap->start; i++) {
> +			lut[i].red = r[i];
> +			lut[i].green = g[i];
> +			lut[i].blue = b[i];
> +		}
> +		for (i = cmap->start + cmap->len; i < size; i++) {
> +			lut[i].red = r[i];
> +			lut[i].green = g[i];
> +			lut[i].blue = b[i];
> +		}
> +	}
> +
> +	for (i = 0; i < cmap->len; i++) {
> +		lut[cmap->start + i].red = cmap->red[i];
> +		lut[cmap->start + i].green = cmap->green[i];
> +		lut[cmap->start + i].blue = cmap->blue[i];
> +	}
> +
> +	return gamma_lut;
> +}
> +
> +static int setcmap_atomic(struct fb_cmap *cmap, struct fb_info *info)
> +{
> +	struct drm_fb_helper *fb_helper = info->par;
> +	struct drm_device *dev = fb_helper->dev;
> +	struct drm_property_blob *gamma_lut = NULL;
> +	struct drm_modeset_acquire_ctx ctx;
> +	struct drm_crtc_state *crtc_state;
> +	struct drm_atomic_state *state;
> +	struct drm_crtc *crtc;
> +	u16 *r, *g, *b;
> +	int i, ret = 0;
> +	bool replaced;
> +
> +	drm_modeset_acquire_init(&ctx, 0);
> +
> +	state = drm_atomic_state_alloc(dev);
> +	if (!state) {
> +		ret = -ENOMEM;
> +		goto out_ctx;
>  	}
>  
> +	state->acquire_ctx = &ctx;
> +retry:
>  	for (i = 0; i < fb_helper->crtc_count; i++) {
>  		crtc = fb_helper->crtc_info[i].mode_set.crtc;
> -		crtc_funcs = crtc->helper_private;
>  
> -		red = cmap->red;
> -		green = cmap->green;
> -		blue = cmap->blue;
> -		transp = cmap->transp;
> -		start = cmap->start;
> -
> -		if (!crtc->gamma_size) {
> -			rc = -EINVAL;
> -			goto out;
> +		if (!gamma_lut)
> +			gamma_lut = setcmap_new_gamma_lut(crtc, cmap);
> +		if (IS_ERR(gamma_lut)) {
> +			ret = PTR_ERR(gamma_lut);
> +			gamma_lut = NULL;
> +			goto out_state;
>  		}
>  
> -		if (cmap->start + cmap->len > crtc->gamma_size) {
> -			rc = -EINVAL;
> -			goto out;
> +		crtc_state = drm_atomic_get_crtc_state(state, crtc);
> +		if (IS_ERR(crtc_state)) {
> +			ret = PTR_ERR(crtc_state);
> +			goto out_state;
>  		}
>  
> +		replaced  = drm_property_replace_blob(&crtc_state->degamma_lut,
> +						      NULL);
> +		replaced |= drm_property_replace_blob(&crtc_state->ctm, NULL);
> +		replaced |= drm_property_replace_blob(&crtc_state->gamma_lut,
> +						      gamma_lut);
> +		crtc_state->color_mgmt_changed |= replaced;
> +	}
> +
> +	ret = drm_atomic_commit(state);
> +	if (ret)
> +		goto out_state;
> +
> +	for (i = 0; i < fb_helper->crtc_count; i++) {
> +		crtc = fb_helper->crtc_info[i].mode_set.crtc;
> +
>  		r = crtc->gamma_store;
>  		g = r + crtc->gamma_size;
>  		b = g + crtc->gamma_size;
> @@ -1306,28 +1366,57 @@ int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
>  		memcpy(r + cmap->start, cmap->red, cmap->len * sizeof(*r));
>  		memcpy(g + cmap->start, cmap->green, cmap->len * sizeof(*g));
>  		memcpy(b + cmap->start, cmap->blue, cmap->len * sizeof(*b));
> +	}
> +
> +out_state:
> +	if (ret == -EDEADLK)
> +		goto backoff;
> +
> +	drm_property_blob_put(gamma_lut);
> +	drm_atomic_state_put(state);
> +out_ctx:
> +	drm_modeset_drop_locks(&ctx);
> +	drm_modeset_acquire_fini(&ctx);
>  
> -		for (j = 0; j < cmap->len; j++) {
> -			u16 hred, hgreen, hblue, htransp = 0xffff;
> +	return ret;
>  
> -			hred = *red++;
> -			hgreen = *green++;
> -			hblue = *blue++;
> +backoff:
> +	drm_atomic_state_clear(state);
> +	drm_modeset_backoff(&ctx);
> +	goto retry;
> +}
>  
> -			if (transp)
> -				htransp = *transp++;
> +/**
> + * drm_fb_helper_setcmap - implementation for &fb_ops.fb_setcmap
> + * @cmap: cmap to set
> + * @info: fbdev registered by the helper
> + */
> +int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
> +{
> +	struct drm_fb_helper *fb_helper = info->par;
> +	int ret;
>  
> -			rc = setcolreg(crtc, hred, hgreen, hblue, start++, info);
> -			if (rc)
> -				goto out;
> -		}
> -		if (crtc_funcs->load_lut)
> -			crtc_funcs->load_lut(crtc);
> +	if (oops_in_progress)
> +		return -EBUSY;
> +
> +	mutex_lock(&fb_helper->lock);
> +
> +	if (!drm_fb_helper_is_bound(fb_helper)) {
> +		ret = -EBUSY;
> +		goto out;
>  	}
> - out:
> -	drm_modeset_unlock_all(dev);
> +
> +	if (info->fix.visual == FB_VISUAL_TRUECOLOR)
> +		ret = setcmap_pseudo_palette(cmap, info);
> +	else if (drm_drv_uses_atomic_modeset(fb_helper->dev))
> +		ret = setcmap_atomic(cmap, info);
> +	else
> +		ret = setcmap_legacy(cmap, info);
> +
> +out:
>  	mutex_unlock(&fb_helper->lock);
> -	return rc;
> +
> +	return ret;
>  }
>  EXPORT_SYMBOL(drm_fb_helper_setcmap);
>  
> -- 
> 2.11.0
> 
> _______________________________________________
> dri-devel mailing list
> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/dri-devel

-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch