Re: [PATCH v2 4/4] drm/msm/disp/dpu1: add PSR support for eDP interface in dpu driver

Stephen Boyd
2022-02-22T21:29:19Z

Quoting Vinod Polimera (2022-02-21 06:51:26)
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> index e7c9fe1..ba3240c 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
> @@ -951,6 +952,14 @@ static void dpu_crtc_disable(struct drm_crtc *crtc,
>
> DRM_DEBUG_KMS("crtc%d\n", crtc->base.id);
>
> + if (old_crtc_state->self_refresh_active) {
> + drm_for_each_encoder_mask(encoder, crtc->dev,
> + old_crtc_state->encoder_mask) {
> + dpu_encoder_assign_crtc(encoder, NULL);
> + }
> + return;
> + }
> +
> /* Disable/save vblank irq handling */
> drm_crtc_vblank_off(crtc);
>
> @@ -962,7 +971,12 @@ static void dpu_crtc_disable(struct drm_crtc *crtc,
> */
> if (dpu_encoder_get_intf_mode(encoder) == INTF_MODE_VIDEO)
> release_bandwidth = true;
> - dpu_encoder_assign_crtc(encoder, NULL);
> + /* If disable is triggered during psr active(e.g: screen dim in PSR),

Multiline comments start with /* on a line by itself

/*
* If disable is triggered ...

> + * we will need encoder->crtc connection to process the device sleep &
> + * preserve it during psr sequence.
> + */
> + if (!crtc->state->self_refresh_active)
> + dpu_encoder_assign_crtc(encoder, NULL);
> }
>
> /* wait for frame_event_done completion */
> @@ -1010,6 +1024,8 @@ static void dpu_crtc_enable(struct drm_crtc *crtc,
> struct dpu_crtc *dpu_crtc = to_dpu_crtc(crtc);
> struct drm_encoder *encoder;
> bool request_bandwidth = false;
> + struct drm_crtc_state *old_crtc_state =
> + drm_atomic_get_old_crtc_state(state, crtc);

Use two lines

struct drm_crtc_state *old_crtc_state;

old_crtc_state = drm_atomic_get_old_crtc_state(state, crtc);

>
> pm_runtime_get_sync(crtc->dev->dev);
>
> @@ -1032,8 +1048,10 @@ static void dpu_crtc_enable(struct drm_crtc *crtc,
> trace_dpu_crtc_enable(DRMID(crtc), true, dpu_crtc);
> dpu_crtc->enabled = true;
>
> - drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state->encoder_mask)
> - dpu_encoder_assign_crtc(encoder, crtc);
> + if (!old_crtc_state->self_refresh_active) {
> + drm_for_each_encoder_mask(encoder, crtc->dev, crtc->state->encoder_mask)
> + dpu_encoder_assign_crtc(encoder, crtc);

Make these two lines above into a function with a meaningful name?
dpu_encoder_assign_crtcs()? And then push the encoder mask iteration
into the loop by passing the mask as a function argument. I see
dpu_encoder_assign_crtc() takes a spinlock, so we could probably take
that lock out too and push it into this new function to avoid grabbing
and dropping the spinlock multiple times.

> + }
>
> /* Enable/restore vblank irq handling */
> drm_crtc_vblank_on(crtc);
> @@ -1497,7 +1515,7 @@ struct drm_crtc *dpu_crtc_init(struct drm_device *dev, struct drm_plane *plane,
> {
> struct drm_crtc *crtc = NULL;
> struct dpu_crtc *dpu_crtc = NULL;
> - int i;
> + int i, ret;
>
> dpu_crtc = kzalloc(sizeof(*dpu_crtc), GFP_KERNEL);
> if (!dpu_crtc)
> @@ -1534,6 +1552,11 @@ struct drm_crtc *dpu_crtc_init(struct drm_device *dev, struct drm_plane *plane,
> /* initialize event handling */
> spin_lock_init(&dpu_crtc->event_lock);
>
> + ret = drm_self_refresh_helper_init(crtc);
> + if (ret)
> + DPU_ERROR("Failed to initialize %s with SR helpers %d\n",

What is SR? Write self-refresh?

> + crtc->name, ret);
> +
> DRM_DEBUG_KMS("%s: successfully initialized crtc\n", dpu_crtc->name);
> return crtc;
> }
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> index 6eac417..ba9d8ea 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_encoder.c
> @@ -217,6 +217,14 @@ static u32 dither_matrix[DITHER_MATRIX_SZ] = {
> 15, 7, 13, 5, 3, 11, 1, 9, 12, 4, 14, 6, 0, 8, 2, 10
> };
>
> +static inline bool is_self_refresh_active(struct drm_crtc_state *state)

const drm_crtc_state?

> +{
> + if (state && state->self_refresh_active)
> + return true;
> +
> + return false;

return state && state->self_refresh_active;

> +}
> +
> static void _dpu_encoder_setup_dither(struct dpu_hw_pingpong *hw_pp, unsigned bpc)
> {
> struct dpu_hw_dither_cfg dither_cfg = { 0 };
> @@ -629,7 +637,8 @@ static int dpu_encoder_virt_atomic_check(
> if (drm_atomic_crtc_needs_modeset(crtc_state)) {
> dpu_rm_release(global_state, drm_enc);
>
> - if (!crtc_state->active_changed || crtc_state->active)
> + if (!crtc_state->active_changed || crtc_state->active ||
> + crtc_state->self_refresh_active)
> ret = dpu_rm_reserve(&dpu_kms->rm, global_state,
> drm_enc, crtc_state, topology);
> }
> @@ -1182,11 +1191,30 @@ static void dpu_encoder_virt_disable(struct drm_encoder *drm_enc,
> {
> struct dpu_encoder_virt *dpu_enc = NULL;
> struct msm_drm_private *priv;
> + struct drm_crtc *crtc;
> + struct drm_crtc_state *old_state;
> int i = 0;
>
> dpu_enc = to_dpu_encoder_virt(drm_enc);
> DPU_DEBUG_ENC(dpu_enc, "\n");

Presumably this print wants a valid 'dpu_enc' pointer.

>
> + if (!drm_enc) {

So this check for !drm_enc is impossible? Please remove it.

> + DPU_ERROR("invalid encoder\n");
> + return;
> + }
> + dpu_enc = to_dpu_encoder_virt(drm_enc);

We got it again?

> +
> + crtc = dpu_enc->crtc;
> +
> + old_state = drm_atomic_get_old_crtc_state(state, crtc);
> +
> + /*
> + * The encoder turn off already occurred when self refresh mode

s/turn off/disable/

> + * was set earlier, in the old_state for the corresponding crtc.
> + */
> + if (drm_enc->encoder_type == DRM_MODE_ENCODER_TMDS && is_self_refresh_active(old_state))
> + return;
> +
> mutex_lock(&dpu_enc->enc_lock);
> dpu_enc->enabled = false;
>
> diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> index 47fe11a..d550f90 100644
> --- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> +++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
> @@ -495,7 +495,7 @@ static void dpu_kms_wait_for_commit_done(struct msm_kms *kms,
> return;
> }
>
> - if (!crtc->state->active) {
> + if (!drm_atomic_crtc_effectively_active(crtc->state)) {
> DPU_DEBUG("[crtc:%d] not active\n", crtc->base.id);
> return;
> }
> --
> 2.7.4
>