Message-ID: <DurUfF_0TBHKv4DHKIP3ggQh_85nRY0usYWn_fu_oJ45txO7dGKv-OK5rl6EDEPmX5l8WzrwPCzAvYz0xFPfeKGyx7enu1g-prsWIpilv88=@proton.me>
Date: Sat, 26 Oct 2024 20:47:42 +0000
From: Piotr Zalewski <pZ010001011111@...ton.me>
To: hjc@...k-chips.com, heiko@...ech.de, andy.yan@...k-chips.com, maarten.lankhorst@...ux.intel.com, mripard@...nel.org, tzimmermann@...e.de, airlied@...il.com, simona@...ll.ch, dri-devel@...ts.freedesktop.org, linux-arm-kernel@...ts.infradead.org, linux-rockchip@...ts.infradead.org, linux-kernel@...r.kernel.org
Cc: skhan@...uxfoundation.org, Piotr Zalewski <pZ010001011111@...ton.me>, Daniel Stone <daniel@...ishbar.org>, Dragan Simic <dsimic@...jaro.org>, Diederik de Haas <didi.debian@...ow.org>
Subject: Re: [PATCH v6] rockchip/drm: vop2: add support for gamma LUT

Hi all,

any comments on this?

On Thursday, October 17th, 2024 at 12:36 AM, Piotr Zalewski <pZ010001011111@...ton.me> wrote:

> Add support for gamma LUT in VOP2 driver. The implementation was inspired
> by one found in VOP1 driver. Blue and red channels in gamma LUT register
> write were swapped with respect to how gamma LUT values are written in
> VOP1. Gamma LUT port selection was added before the write of new gamma LUT
> table.
> 
> If the current SoC is rk356x, check if no other CRTC has gamma LUT enabled
> in atomic_check (only one video port can use gamma LUT at a time) and
> disable gamma LUT before the LUT table write.
> 
> If the current SoC isn't rk356x, "seamless" gamma lut update is performed
> similarly to how it was done in the case of RK3399 in VOP1[1]. In seamless
> update gamma LUT disable before the write isn't necessary, check if no
> other CRTC has gamma LUT enabled is also not necessary, different register
> is being used to select gamma LUT port[2] and after setting DSP_LUT_EN bit,
> GAMMA_UPDATE_EN bit is set[3].
> 
> Gamma size is set and drm color management is enabled for each video port's
> CRTC except ones which have no associated device.
> 
> Solution was tested on RK3566 (Pinetab2). When using userspace tools
> which set eg. constant color temperature no issues were noticed. When
> using userspace tools which adjust eg. color temperature the slight screen
> flicker is visible probably because of gamma LUT disable.
> 
> Compare behaviour of eg.:
> `gammastep -O 3000`
> 
> To eg.:
> `gammastep -l 53:23 -t 6000:3000`
> 
> In latter case color temperature is slowly adjusted at the beginning which
> causes screen to slighly flicker. Then it adjusts every few seconds which
> also causes slight screen flicker.
> 
> [1] https://lists.infradead.org/pipermail/linux-rockchip/2021-October/028132.html
> [2] https://lore.kernel.org/linux-rockchip/48249708-8c05-40d2-a5d8-23de960c5a77@rock-chips.com/
> [3] https://github.com/radxa/kernel/blob/linux-6.1-stan-rkr1/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c#L3437
> 
> Helped-by: Daniel Stone daniel@...ishbar.org
> 
> Helped-by: Dragan Simic dsimic@...jaro.org
> 
> Helped-by: Diederik de Haas didi.debian@...ow.org
> 
> Helped-by: Andy Yan andy.yan@...k-chips.com
> 
> Signed-off-by: Piotr Zalewski pZ010001011111@...ton.me
> 
> ---
> 
> Notes:
> Changes in v6:
> - Move gamma lut write to atomic_flush[4].
> - In atomic_check if any other than the currently updated CRTC has
> gamma lut enabled, return -EINVAL [5] (perform a check only if
> device is rk356x).
> - Instead of checking for rk3588 to determine seamless gamma
> update availability check for rk3566/rk3568.
> - remove null check in vop2_create_crtcs
> - Move some code to separate functions to increase readability.
> 
> Changes in v5:
> - Do not trigger full modeset in case seamless gamma lut update
> isn't possible (eg. rk356x case). It was discovered that with
> full modeset, userspace tools which adjust color temperature with
> high frequency cause screen to go black and reduce overall
> performance. Instead, revert to previous behaviour of lut update
> happening in atomic_begin or (in case there is a modeset) in
> atomic_enable. Also, add unrelated to modeset trigger
> changes/improvements from v4 on top. Improve code readability
> too.
> 
> Changes in v4:
> - rework the implementation to better utilize DRM atomic updates[2]
> - handle the RK3588 case[2][3]
> 
> Changes in v3:
> - v3 is patch v2 "resend", by mistake the incremental patch was
> sent in v2
> 
> Changes in v2:
> - Apply code styling corrections[1]
> - Move gamma LUT write inside the vop2 lock
> 
> Link to v5: https://lore.kernel.org/linux-rockchip/20241014222022.571819-4-pZ010001011111@proton.me/
> Link to v4: https://lore.kernel.org/linux-rockchip/20240815124306.189282-2-pZ010001011111@proton.me/
> Link to v3: https://lore.kernel.org/linux-rockchip/TkgKVivuaLFLILPY-n3iZo_8KF-daKdqdu-0_e0HP-5Ar_8DALDeNWog2suwWKjX7eomcbGET0KZe7DlzdhK2YM6CbLbeKeFZr-MJzJMtw0=@proton.me/
> Link to v2: https://lore.kernel.org/linux-rockchip/Hk03HDb6wSSHWtEFZHUye06HR0-9YzP5nCHx9A8_kHzWSZawDrU1o1pjEGkCOJFoRg0nTB4BWEv6V0XBOjF4-0Mj44lp2TrjaQfnytzp-Pk=@proton.me/
> Link to v1: https://lore.kernel.org/linux-rockchip/ZVMxgcrtgHui9fJpnhbN6TSPhofHbbXElh241lImrzzTUl-8WejGpaR8CPzYhBgoqe_xj7N6En8Ny7Z-gsCr0kaFs7apwjYV1MBJJLmLHxs=@proton.me/
> 
> [1] https://lore.kernel.org/linux-rockchip/d019761504b540600d9fc7a585d6f95f@manjaro.org
> [2] https://lore.kernel.org/linux-rockchip/CAPj87rOM=j0zmuWL9frGKV1xzPbJrk=Q9ip7F_HAPYnbCqPouw@mail.gmail.com
> [3] https://lore.kernel.org/linux-rockchip/7d998e4c-e1d3-4e8b-af76-c5bc83b43647@rock-chips.com
> [4] https://lore.kernel.org/linux-rockchip/7b45f190.452f.1928e41b746.Coremail.andyshrk@163.com/
> [5] https://lore.kernel.org/linux-rockchip/CAPj87rOdQPsuH9qB_ZLfC9S=cO2noNi1mOGW0ZmQ6SHCugb9=w@mail.gmail.com/
> 
> drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 189 +++++++++++++++++++
> drivers/gpu/drm/rockchip/rockchip_drm_vop2.h | 5 +
> 2 files changed, 194 insertions(+)
> 
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> index 9873172e3fd3..6018c353e66b 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
> @@ -278,6 +278,15 @@ static u32 vop2_readl(struct vop2 *vop2, u32 offset)
> return val;
> }
> 
> +static u32 vop2_vp_read(struct vop2_video_port *vp, u32 offset)
> +{
> + u32 val;
> +
> + regmap_read(vp->vop2->map, vp->data->offset + offset, &val);
> 
> +
> + return val;
> +}
> +
> static void vop2_win_write(const struct vop2_win *win, unsigned int reg, u32 v)
> {
> regmap_field_write(win->reg[reg], v);
> 
> @@ -998,6 +1007,65 @@ static void vop2_disable(struct vop2 *vop2)
> clk_disable_unprepare(vop2->hclk);
> 
> }
> 
> +static bool vop2_vp_dsp_lut_is_enabled(struct vop2_video_port *vp)
> +{
> + return (u32) (vop2_vp_read(vp, RK3568_VP_DSP_CTRL) & RK3568_VP_DSP_CTRL__DSP_LUT_EN) >
> 
> + 0;
> +}
> +
> +static void vop2_vp_dsp_lut_disable(struct vop2_video_port *vp)
> +{
> + u32 dsp_ctrl = vop2_vp_read(vp, RK3568_VP_DSP_CTRL);
> +
> + dsp_ctrl &= ~RK3568_VP_DSP_CTRL__DSP_LUT_EN;
> + vop2_vp_write(vp, RK3568_VP_DSP_CTRL, dsp_ctrl);
> +}
> +
> +static bool vop2_vp_dsp_lut_poll_disable(struct vop2_video_port *vp)
> +{
> + u32 dsp_ctrl;
> + int ret = readx_poll_timeout(vop2_vp_dsp_lut_is_enabled, vp, dsp_ctrl,
> + !dsp_ctrl, 5, 30 * 1000);
> + if (ret) {
> + drm_err(vp->vop2->drm, "display LUT RAM enable timeout!\n");
> 
> + return false;
> + }
> +
> + return true;
> +}
> +
> +static void vop2_vp_dsp_lut_enable(struct vop2_video_port *vp)
> +{
> + u32 dsp_ctrl = vop2_vp_read(vp, RK3568_VP_DSP_CTRL);
> +
> + dsp_ctrl |= RK3568_VP_DSP_CTRL__DSP_LUT_EN;
> + vop2_vp_write(vp, RK3568_VP_DSP_CTRL, dsp_ctrl);
> +}
> +
> +static void vop2_vp_dsp_lut_update_enable(struct vop2_video_port *vp)
> +{
> + u32 dsp_ctrl = vop2_vp_read(vp, RK3568_VP_DSP_CTRL);
> +
> + dsp_ctrl |= RK3588_VP_DSP_CTRL__GAMMA_UPDATE_EN;
> + vop2_vp_write(vp, RK3568_VP_DSP_CTRL, dsp_ctrl);
> +}
> +
> +static inline bool vop2_supports_seamless_gamma_lut_update(struct vop2 *vop2)
> +{
> + return (vop2->data->soc_id != 3566 && vop2->data->soc_id != 3568);
> 
> +}
> +
> +static bool vop2_gamma_lut_in_use(struct vop2 *vop2, struct vop2_video_port *vp)
> +{
> + const int nr_vps = vop2->data->nr_vps;
> 
> + int gamma_en_vp_id;
> + for (gamma_en_vp_id = 0; gamma_en_vp_id < nr_vps; gamma_en_vp_id++)
> + if (vop2_vp_dsp_lut_is_enabled(&vop2->vps[gamma_en_vp_id]))
> 
> + break;
> +
> + return gamma_en_vp_id != nr_vps && gamma_en_vp_id != vp->id;
> 
> +}
> +
> static void vop2_crtc_atomic_disable(struct drm_crtc *crtc,
> struct drm_atomic_state *state)
> {
> @@ -1482,6 +1550,80 @@ static bool vop2_crtc_mode_fixup(struct drm_crtc *crtc,
> return true;
> }
> 
> +static void vop2_crtc_write_gamma_lut(struct vop2 *vop2, struct drm_crtc *crtc)
> +{
> + const struct vop2_video_port *vp = to_vop2_video_port(crtc);
> + const struct vop2_video_port_data *vp_data = &vop2->data->vp[vp->id];
> 
> +
> + struct drm_color_lut *lut = crtc->state->gamma_lut->data;
> 
> + unsigned int i, bpc = ilog2(vp_data->gamma_lut_len);
> 
> + u32 word;
> +
> + for (i = 0; i < crtc->gamma_size; i++) {
> 
> + word = (drm_color_lut_extract(lut[i].blue, bpc) << (2 * bpc)) |
> + (drm_color_lut_extract(lut[i].green, bpc) << bpc) |
> + drm_color_lut_extract(lut[i].red, bpc);
> +
> + writel(word, vop2->lut_regs + i * 4);
> 
> + }
> +}
> +
> +static void vop2_crtc_atomic_set_gamma_seamless(struct vop2 *vop2,
> + struct vop2_video_port *vp,
> + struct drm_crtc *crtc)
> +{
> + vop2_writel(vop2, RK3568_LUT_PORT_SEL, FIELD_PREP(
> + RK3588_LUT_PORT_SEL__GAMMA_AHB_WRITE_SEL,
> + vp->id));
> 
> + vop2_vp_dsp_lut_enable(vp);
> + vop2_crtc_write_gamma_lut(vop2, crtc);
> + vop2_vp_dsp_lut_update_enable(vp);
> +}
> +
> +static void vop2_crtc_atomic_set_gamma_rk356x(struct vop2 *vop2,
> + struct vop2_video_port *vp,
> + struct drm_crtc *crtc)
> +{
> + vop2_vp_dsp_lut_disable(vp);
> + vop2_cfg_done(vp);
> + if (!vop2_vp_dsp_lut_poll_disable(vp))
> + return;
> +
> + vop2_writel(vop2, RK3568_LUT_PORT_SEL, vp->id);
> 
> + vop2_crtc_write_gamma_lut(vop2, crtc);
> + vop2_vp_dsp_lut_enable(vp);
> +}
> +
> +static void vop2_crtc_atomic_try_set_gamma(struct vop2 *vop2,
> + struct vop2_video_port *vp,
> + struct drm_crtc *crtc,
> + struct drm_crtc_state *crtc_state)
> +{
> +
> + if (!vop2->lut_regs || !crtc_state->color_mgmt_changed)
> 
> + return;
> +
> + if (!crtc_state->gamma_lut) {
> 
> + vop2_vp_dsp_lut_disable(vp);
> + return;
> + }
> +
> + if (vop2_supports_seamless_gamma_lut_update(vop2))
> + vop2_crtc_atomic_set_gamma_seamless(vop2, vp, crtc);
> + else
> + vop2_crtc_atomic_set_gamma_rk356x(vop2, vp, crtc);
> +}
> +
> +static inline void vop2_crtc_atomic_try_set_gamma_locked(struct vop2 *vop2,
> + struct vop2_video_port *vp,
> + struct drm_crtc *crtc,
> + struct drm_crtc_state *crtc_state)
> +{
> + vop2_lock(vop2);
> + vop2_crtc_atomic_try_set_gamma(vop2, vp, crtc, crtc_state);
> + vop2_unlock(vop2);
> +}
> +
> static void vop2_dither_setup(struct drm_crtc *crtc, u32 *dsp_ctrl)
> {
> struct rockchip_crtc_state *vcstate = to_rockchip_crtc_state(crtc->state);
> 
> @@ -2057,11 +2199,40 @@ static void vop2_crtc_atomic_enable(struct drm_crtc *crtc,
> 
> vop2_vp_write(vp, RK3568_VP_DSP_CTRL, dsp_ctrl);
> 
> + vop2_crtc_atomic_try_set_gamma(vop2, vp, crtc, crtc_state);
> +
> drm_crtc_vblank_on(crtc);
> 
> vop2_unlock(vop2);
> }
> 
> +static int vop2_crtc_atomic_check_gamma(struct vop2_video_port *vp,
> + struct drm_crtc *crtc,
> + struct drm_atomic_state *state,
> + struct drm_crtc_state *crtc_state)
> +{
> + struct vop2 *vop2 = vp->vop2;
> 
> + unsigned int len;
> +
> + if (!vp->vop2->lut_regs || !crtc_state->color_mgmt_changed ||
> 
> + !crtc_state->gamma_lut)
> 
> + return 0;
> +
> + len = drm_color_lut_size(crtc_state->gamma_lut);
> 
> + if (len != crtc->gamma_size) {
> 
> + drm_dbg(vop2->drm, "Invalid LUT size; got %d, expected %d\n",
> 
> + len, crtc->gamma_size);
> 
> + return -EINVAL;
> + }
> +
> + if (!vop2_supports_seamless_gamma_lut_update(vop2) && vop2_gamma_lut_in_use(vop2, vp)) {
> + drm_info(vop2->drm, "Gamma LUT can be enabled for only one CRTC at a time\n");
> 
> + return -EINVAL;
> + }
> +
> + return 0;
> +}
> +
> static int vop2_crtc_atomic_check(struct drm_crtc *crtc,
> struct drm_atomic_state *state)
> {
> @@ -2069,6 +2240,11 @@ static int vop2_crtc_atomic_check(struct drm_crtc *crtc,
> struct drm_plane *plane;
> int nplanes = 0;
> struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
> + int ret;
> +
> + ret = vop2_crtc_atomic_check_gamma(vp, crtc, state, crtc_state);
> + if (ret)
> + return ret;
> 
> drm_atomic_crtc_state_for_each_plane(plane, crtc_state)
> nplanes++;
> @@ -2456,6 +2632,7 @@ static void vop2_setup_dly_for_windows(struct vop2 *vop2)
> vop2_writel(vop2, RK3568_SMART_DLY_NUM, sdly);
> }
> 
> +
> static void vop2_crtc_atomic_begin(struct drm_crtc *crtc,
> struct drm_atomic_state *state)
> {
> @@ -2487,7 +2664,14 @@ static void vop2_crtc_atomic_begin(struct drm_crtc *crtc,
> static void vop2_crtc_atomic_flush(struct drm_crtc *crtc,
> struct drm_atomic_state *state)
> {
> + struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
> struct vop2_video_port *vp = to_vop2_video_port(crtc);
> + struct vop2 *vop2 = vp->vop2;
> 
> +
> + // NOTE: in case of modeset gamma lut update
> + // already happened in atomic enable
> + if (!drm_atomic_crtc_needs_modeset(crtc_state))
> + vop2_crtc_atomic_try_set_gamma_locked(vop2, vp, crtc, crtc_state);
> 
> vop2_post_config(crtc);
> 
> @@ -2790,7 +2974,12 @@ static int vop2_create_crtcs(struct vop2 *vop2)
> }
> 
> drm_crtc_helper_add(&vp->crtc, &vop2_crtc_helper_funcs);
> 
> + if (vop2->lut_regs) {
> 
> + const struct vop2_video_port_data *vp_data = &vop2_data->vp[vp->id];
> 
> 
> + drm_mode_crtc_set_gamma_size(&vp->crtc, vp_data->gamma_lut_len);
> 
> + drm_crtc_enable_color_mgmt(&vp->crtc, 0, false, vp_data->gamma_lut_len);
> 
> + }
> init_completion(&vp->dsp_hold_completion);
> 
> }
> 
> diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.h b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.h
> index 615a16196aff..510dda6f9092 100644
> --- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.h
> +++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.h
> @@ -394,6 +394,7 @@ enum dst_factor_mode {
> #define RK3568_REG_CFG_DONE__GLB_CFG_DONE_EN BIT(15)
> 
> #define RK3568_VP_DSP_CTRL__STANDBY BIT(31)
> +#define RK3568_VP_DSP_CTRL__DSP_LUT_EN BIT(28)
> #define RK3568_VP_DSP_CTRL__DITHER_DOWN_MODE BIT(20)
> #define RK3568_VP_DSP_CTRL__DITHER_DOWN_SEL GENMASK(19, 18)
> #define RK3568_VP_DSP_CTRL__DITHER_DOWN_EN BIT(17)
> @@ -408,6 +409,8 @@ enum dst_factor_mode {
> #define RK3568_VP_DSP_CTRL__CORE_DCLK_DIV BIT(4)
> #define RK3568_VP_DSP_CTRL__OUT_MODE GENMASK(3, 0)
> 
> +#define RK3588_VP_DSP_CTRL__GAMMA_UPDATE_EN BIT(22)
> +
> #define RK3588_VP_CLK_CTRL__DCLK_OUT_DIV GENMASK(3, 2)
> #define RK3588_VP_CLK_CTRL__DCLK_CORE_DIV GENMASK(1, 0)
> 
> @@ -460,6 +463,8 @@ enum dst_factor_mode {
> #define RK3588_DSP_IF_POL__DP1_PIN_POL GENMASK(14, 12)
> #define RK3588_DSP_IF_POL__DP0_PIN_POL GENMASK(10, 8)
> 
> +#define RK3588_LUT_PORT_SEL__GAMMA_AHB_WRITE_SEL GENMASK(13, 12)
> +
> #define RK3568_VP0_MIPI_CTRL__DCLK_DIV2_PHASE_LOCK BIT(5)
> #define RK3568_VP0_MIPI_CTRL__DCLK_DIV2 BIT(4)
> 
> --
> 2.47.0

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