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

From: Daniel Vetter
Date: Fri Jul 14 2017 - 09:54:38 EST


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