Hi Detlev，
At 2024-05-23 02:57:48, "Detlev Casanova" <detlev.casan...@collabora.com> wrote:
>At the end of initialization, each VP clock needs to be reset before
>they can be used.
>
>Failing to do so can put the VOP in an undefined state where the
>generated HDMI signal is either lost or not matching the selected mode.
Would you please provide a detailed description of your test case?
>
>Signed-off-by: Detlev Casanova <detlev.casan...@collabora.com>
>---
> drivers/gpu/drm/rockchip/rockchip_drm_vop2.c | 30 ++++++++++++++++++++
> 1 file changed, 30 insertions(+)
>
>diff --git a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
>b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
>index fdd768bbd487c..e81a67161d29a 100644
>--- a/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
>+++ b/drivers/gpu/drm/rockchip/rockchip_drm_vop2.c
>@@ -17,6 +17,7 @@
> #include <linux/platform_device.h>
> #include <linux/pm_runtime.h>
> #include <linux/regmap.h>
>+#include <linux/reset.h>
> #include <linux/swab.h>
>
> #include <drm/drm.h>
>@@ -157,6 +158,7 @@ struct vop2_win {
> struct vop2_video_port {
> struct drm_crtc crtc;
> struct vop2 *vop2;
>+ struct reset_control *dclk_rst;
> struct clk *dclk;
> unsigned int id;
> const struct vop2_video_port_data *data;
>@@ -1915,6 +1917,26 @@ static int us_to_vertical_line(struct drm_display_mode
>*mode, int us)
> return us * mode->clock / mode->htotal / 1000;
> }
>
>+static int vop2_clk_reset(struct vop2_video_port *vp)
>+{
>+ struct reset_control *rstc = vp->dclk_rst;
>+ struct vop2 *vop2 = vp->vop2;
>+ int ret;
>+
>+ if (!rstc)
>+ return 0;
In fact, this check is not necessary here. The following reset control api
will check for NULL pointer。
>+
>+ ret = reset_control_assert(rstc);
>+ if (ret < 0)
>+ drm_warn(vop2->drm, "failed to assert reset\n");
>+ udelay(10);
>+ ret = reset_control_deassert(rstc);
>+ if (ret < 0)
>+ drm_warn(vop2->drm, "failed to deassert reset\n");
>+
>+ return ret;
>+}
>+
> static void vop2_crtc_atomic_enable(struct drm_crtc *crtc,
> struct drm_atomic_state *state)
> {
>@@ -2055,6 +2077,8 @@ static void vop2_crtc_atomic_enable(struct drm_crtc
>*crtc,
>
> vop2_vp_write(vp, RK3568_VP_DSP_CTRL, dsp_ctrl);
>
>+ vop2_clk_reset(vp);
>+
> drm_crtc_vblank_on(crtc);
>
> vop2_unlock(vop2);
>@@ -2706,6 +2730,12 @@ static int vop2_create_crtcs(struct vop2 *vop2)
> vp->data = vp_data;
>
> snprintf(dclk_name, sizeof(dclk_name), "dclk_vp%d", vp->id);
>+ vp->dclk_rst = devm_reset_control_get_optional(vop2->dev,
>dclk_name);
>+ if (IS_ERR(vp->dclk_rst)) {
>+ drm_err(vop2->drm, "failed to get %s reset\n",
>dclk_name);
>+ return PTR_ERR(vp->dclk_rst);
>+ }
>+
> vp->dclk = devm_clk_get(vop2->dev, dclk_name);
> if (IS_ERR(vp->dclk)) {
> drm_err(vop2->drm, "failed to get %s\n", dclk_name);
>--
>2.44.1
>
>
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