Re: [PATCH 08/30] drm/sun4i: ui layer: Write attributes in one go
From: Chen-Yu Tsai <hidden>
Date: 2025-10-27 16:04:59
Also in:
dri-devel, linux-sunxi, lkml
On Mon, Oct 13, 2025 at 3:23 AM Jernej Skrabec [off-list ref] wrote:
It turns out that none of the UI channel registers were meant to be read. Mostly it works fine but sometimes it returns incorrect values. Rework UI layer code to write all registers in one go to avoid reads. This rework will also allow proper code separation. Signed-off-by: Jernej Skrabec <jernej.skrabec@gmail.com>
Reviewed-by: Chen-Yu Tsai <wens@kernel.org>
quoted hunk ↗ jump to hunk
--- drivers/gpu/drm/sun4i/sun8i_ui_layer.c | 50 +++++++++----------------- 1 file changed, 16 insertions(+), 34 deletions(-)diff --git a/drivers/gpu/drm/sun4i/sun8i_ui_layer.c b/drivers/gpu/drm/sun4i/sun8i_ui_layer.c index 12c83c54f9bc..8634d2ee613a 100644 --- a/drivers/gpu/drm/sun4i/sun8i_ui_layer.c +++ b/drivers/gpu/drm/sun4i/sun8i_ui_layer.c@@ -25,25 +25,27 @@ #include "sun8i_ui_scaler.h" #include "sun8i_vi_scaler.h" -static void sun8i_ui_layer_update_alpha(struct sun8i_mixer *mixer, int channel, - int overlay, struct drm_plane *plane) +static void sun8i_ui_layer_update_attributes(struct sun8i_mixer *mixer, + int channel, int overlay, + struct drm_plane *plane) { - u32 mask, val, ch_base; + struct drm_plane_state *state = plane->state; + const struct drm_format_info *fmt; + u32 val, ch_base, hw_fmt; ch_base = sun8i_channel_base(mixer, channel); + fmt = state->fb->format; + sun8i_mixer_drm_format_to_hw(fmt->format, &hw_fmt); - mask = SUN8I_MIXER_CHAN_UI_LAYER_ATTR_ALPHA_MODE_MASK | - SUN8I_MIXER_CHAN_UI_LAYER_ATTR_ALPHA_MASK; - - val = SUN8I_MIXER_CHAN_UI_LAYER_ATTR_ALPHA(plane->state->alpha >> 8); - - val |= (plane->state->alpha == DRM_BLEND_ALPHA_OPAQUE) ? + val = SUN8I_MIXER_CHAN_UI_LAYER_ATTR_ALPHA(state->alpha >> 8); + val |= (state->alpha == DRM_BLEND_ALPHA_OPAQUE) ?
Changing "plane->state" to "state" made the diff somewhat harder to read.
quoted hunk ↗ jump to hunk
SUN8I_MIXER_CHAN_UI_LAYER_ATTR_ALPHA_MODE_PIXEL : SUN8I_MIXER_CHAN_UI_LAYER_ATTR_ALPHA_MODE_COMBINED; + val |= hw_fmt << SUN8I_MIXER_CHAN_UI_LAYER_ATTR_FBFMT_OFFSET; + val |= SUN8I_MIXER_CHAN_UI_LAYER_ATTR_EN; - regmap_update_bits(mixer->engine.regs, - SUN8I_MIXER_CHAN_UI_LAYER_ATTR(ch_base, overlay), - mask, val); + regmap_write(mixer->engine.regs, + SUN8I_MIXER_CHAN_UI_LAYER_ATTR(ch_base, overlay), val); } static void sun8i_ui_layer_update_coord(struct sun8i_mixer *mixer, int channel,@@ -111,24 +113,6 @@ static void sun8i_ui_layer_update_coord(struct sun8i_mixer *mixer, int channel, } } -static void sun8i_ui_layer_update_formats(struct sun8i_mixer *mixer, int channel, - int overlay, struct drm_plane *plane) -{ - struct drm_plane_state *state = plane->state; - const struct drm_format_info *fmt; - u32 val, ch_base, hw_fmt; - - ch_base = sun8i_channel_base(mixer, channel); - - fmt = state->fb->format; - sun8i_mixer_drm_format_to_hw(fmt->format, &hw_fmt); - - val = hw_fmt << SUN8I_MIXER_CHAN_UI_LAYER_ATTR_FBFMT_OFFSET; - regmap_update_bits(mixer->engine.regs, - SUN8I_MIXER_CHAN_UI_LAYER_ATTR(ch_base, overlay), - SUN8I_MIXER_CHAN_UI_LAYER_ATTR_FBFMT_MASK, val); -} - static void sun8i_ui_layer_update_buffer(struct sun8i_mixer *mixer, int channel, int overlay, struct drm_plane *plane) {@@ -220,12 +204,10 @@ static void sun8i_ui_layer_atomic_update(struct drm_plane *plane, if (!new_state->crtc || !new_state->visible) return; + sun8i_ui_layer_update_attributes(mixer, layer->channel, + layer->overlay, plane); sun8i_ui_layer_update_coord(mixer, layer->channel, layer->overlay, plane); - sun8i_ui_layer_update_alpha(mixer, layer->channel, - layer->overlay, plane); - sun8i_ui_layer_update_formats(mixer, layer->channel, - layer->overlay, plane); sun8i_ui_layer_update_buffer(mixer, layer->channel, layer->overlay, plane); } --2.51.0