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Message-Id: <20220219193957.577054-1-robdclark@gmail.com>
Date: Sat, 19 Feb 2022 11:39:43 -0800
From: Rob Clark <robdclark@...il.com>
To: dri-devel@...ts.freedesktop.org
Cc: freedreno@...ts.freedesktop.org, linux-arm-msm@...r.kernel.org,
Rob Clark <robdclark@...omium.org>,
Rob Clark <robdclark@...il.com>, Sean Paul <sean@...rly.run>,
Abhinav Kumar <quic_abhinavk@...cinc.com>,
David Airlie <airlied@...ux.ie>,
Daniel Vetter <daniel@...ll.ch>,
Dmitry Baryshkov <dmitry.baryshkov@...aro.org>,
Kalyan Thota <quic_kalyant@...cinc.com>,
Stephen Boyd <swboyd@...omium.org>,
Krishna Manikandan <quic_mkrishn@...cinc.com>,
Mark Yacoub <markyacoub@...gle.com>,
Jessica Zhang <quic_jesszhan@...cinc.com>,
Bjorn Andersson <bjorn.andersson@...aro.org>,
Yangtao Li <tiny.windzz@...il.com>,
David Heidelberg <david@...t.cz>, Xu Wang <vulab@...as.ac.cn>,
AngeloGioacchino Del Regno
<angelogioacchino.delregno@...labora.com>,
linux-kernel@...r.kernel.org (open list)
Subject: [PATCH] drm/msm: Avoid dirtyfb stalls on video mode displays
From: Rob Clark <robdclark@...omium.org>
Someone on IRC once asked an innocent enough sounding question: Why
with xf86-video-modesetting is es2gears limited at 120fps.
So I broke out the perfetto tracing mesa MR and took a look. It turns
out the problem was drm_atomic_helper_dirtyfb(), which would end up
waiting for vblank.. es2gears would rapidly push two frames to Xorg,
which would blit them to screen and in idle hook (I assume) call the
DIRTYFB ioctl. Which in turn would do an atomic update to flush the
dirty rects, which would stall until the next vblank. And then the
whole process would repeat.
But this is a bit silly, we only need dirtyfb for command mode DSI
panels. So lets just skip it otherwise.
Signed-off-by: Rob Clark <robdclark@...omium.org>
---
drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c | 13 +++++
drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h | 9 ++++
drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c | 1 +
drivers/gpu/drm/msm/disp/mdp4/mdp4_crtc.c | 9 ++++
drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c | 1 +
drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h | 1 +
drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c | 8 +++
drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c | 1 +
drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h | 1 +
drivers/gpu/drm/msm/msm_fb.c | 64 ++++++++++++++++++++++-
drivers/gpu/drm/msm/msm_kms.h | 2 +
11 files changed, 109 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
index e7c9fe1a250f..3706053bc164 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.c
@@ -265,6 +265,19 @@ static bool dpu_crtc_get_scanout_position(struct drm_crtc *crtc,
return true;
}
+bool dpu_crtc_needs_dirtyfb(struct drm_crtc *crtc)
+{
+ struct drm_encoder *encoder;
+
+ drm_for_each_encoder_mask (encoder, crtc->dev, crtc->state->encoder_mask) {
+ if (dpu_encoder_get_intf_mode(encoder) == INTF_MODE_CMD) {
+ return true;
+ }
+ }
+
+ return false;
+}
+
static void _dpu_crtc_setup_blend_cfg(struct dpu_crtc_mixer *mixer,
struct dpu_plane_state *pstate, struct dpu_format *format)
{
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
index b8785c394fcc..64f79b22aba7 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_crtc.h
@@ -261,6 +261,15 @@ void dpu_crtc_commit_kickoff(struct drm_crtc *crtc);
*/
void dpu_crtc_complete_commit(struct drm_crtc *crtc);
+/**
+ * dpu_crtc_needs_dirtyfb - do fb updates need to be flushed
+ * @crtc: Pointer to drm crtc object
+ *
+ * Return whether front-buffer updates need to be flushed, ie. is it
+ * a command-mode style of display
+ */
+bool dpu_crtc_needs_dirtyfb(struct drm_crtc *crtc);
+
/**
* dpu_crtc_init - create a new crtc object
* @dev: dpu device
diff --git a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
index 47fe11a84a77..84d9521e8013 100644
--- a/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
+++ b/drivers/gpu/drm/msm/disp/dpu1/dpu_kms.c
@@ -949,6 +949,7 @@ static const struct msm_kms_funcs kms_funcs = {
.check_modified_format = dpu_format_check_modified_format,
.get_format = dpu_get_msm_format,
.round_pixclk = dpu_kms_round_pixclk,
+ .needs_dirtyfb = dpu_crtc_needs_dirtyfb,
.destroy = dpu_kms_destroy,
.snapshot = dpu_kms_mdp_snapshot,
#ifdef CONFIG_DEBUG_FS
diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_crtc.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_crtc.c
index 169f9de4a12a..64ff21cfed03 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_crtc.c
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_crtc.c
@@ -19,6 +19,7 @@ struct mdp4_crtc {
int id;
int ovlp;
enum mdp4_dma dma;
+ enum mdp4_intf intf;
bool enabled;
/* which mixer/encoder we route output to: */
@@ -594,6 +595,7 @@ void mdp4_crtc_set_intf(struct drm_crtc *crtc, enum mdp4_intf intf, int mixer)
intf_sel |= MDP4_DISP_INTF_SEL_DSI_CMD;
}
+ mdp4_crtc->intf = intf;
mdp4_crtc->mixer = mixer;
blend_setup(crtc);
@@ -612,6 +614,13 @@ void mdp4_crtc_wait_for_commit_done(struct drm_crtc *crtc)
mdp4_crtc_wait_for_flush_done(crtc);
}
+bool mdp4_crtc_needs_dirtyfb(struct drm_crtc *crtc)
+{
+ struct mdp4_crtc *mdp4_crtc = to_mdp4_crtc(crtc);
+
+ return mdp4_crtc->intf == INTF_DSI_CMD;
+}
+
static const char *dma_names[] = {
"DMA_P", "DMA_S", "DMA_E",
};
diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
index 5a33bb148e9e..5e1d19df5c18 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.c
@@ -163,6 +163,7 @@ static const struct mdp_kms_funcs kms_funcs = {
.complete_commit = mdp4_complete_commit,
.get_format = mdp_get_format,
.round_pixclk = mdp4_round_pixclk,
+ .needs_dirtyfb = mdp4_crtc_needs_dirtyfb,
.destroy = mdp4_destroy,
},
.set_irqmask = mdp4_set_irqmask,
diff --git a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
index e8ee92ab7956..1633ec866b49 100644
--- a/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
+++ b/drivers/gpu/drm/msm/disp/mdp4/mdp4_kms.h
@@ -190,6 +190,7 @@ uint32_t mdp4_crtc_vblank(struct drm_crtc *crtc);
void mdp4_crtc_set_config(struct drm_crtc *crtc, uint32_t config);
void mdp4_crtc_set_intf(struct drm_crtc *crtc, enum mdp4_intf intf, int mixer);
void mdp4_crtc_wait_for_commit_done(struct drm_crtc *crtc);
+bool mdp4_crtc_needs_dirtyfb(struct drm_crtc *crtc);
struct drm_crtc *mdp4_crtc_init(struct drm_device *dev,
struct drm_plane *plane, int id, int ovlp_id,
enum mdp4_dma dma_id);
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
index bb7d066618e6..fac2cfd3ef7e 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_crtc.c
@@ -1300,6 +1300,14 @@ void mdp5_crtc_wait_for_commit_done(struct drm_crtc *crtc)
mdp5_crtc_wait_for_flush_done(crtc);
}
+bool mdp5_crtc_needs_dirtyfb(struct drm_crtc *crtc)
+{
+ struct mdp5_crtc_state *mdp5_cstate = to_mdp5_crtc_state(crtc->state);
+ struct mdp5_interface *intf = mdp5_cstate->pipeline.intf;
+
+ return intf->mode == MDP5_INTF_DSI_MODE_COMMAND;
+}
+
/* initialize crtc */
struct drm_crtc *mdp5_crtc_init(struct drm_device *dev,
struct drm_plane *plane,
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
index 12a5f81e402b..25a474732e7f 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.c
@@ -280,6 +280,7 @@ static const struct mdp_kms_funcs kms_funcs = {
.get_format = mdp_get_format,
.round_pixclk = mdp5_round_pixclk,
.set_split_display = mdp5_set_split_display,
+ .needs_dirtyfb = mdp5_crtc_needs_dirtyfb,
.destroy = mdp5_kms_destroy,
#ifdef CONFIG_DEBUG_FS
.debugfs_init = mdp5_kms_debugfs_init,
diff --git a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h
index ac269a6802df..ae62f6778346 100644
--- a/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h
+++ b/drivers/gpu/drm/msm/disp/mdp5/mdp5_kms.h
@@ -280,6 +280,7 @@ struct mdp5_hw_mixer *mdp5_crtc_get_mixer(struct drm_crtc *crtc);
struct mdp5_pipeline *mdp5_crtc_get_pipeline(struct drm_crtc *crtc);
void mdp5_crtc_set_pipeline(struct drm_crtc *crtc);
void mdp5_crtc_wait_for_commit_done(struct drm_crtc *crtc);
+bool mdp5_crtc_needs_dirtyfb(struct drm_crtc *crtc);
struct drm_crtc *mdp5_crtc_init(struct drm_device *dev,
struct drm_plane *plane,
struct drm_plane *cursor_plane, int id);
diff --git a/drivers/gpu/drm/msm/msm_fb.c b/drivers/gpu/drm/msm/msm_fb.c
index 4d34df5354e0..1b0648baeae2 100644
--- a/drivers/gpu/drm/msm/msm_fb.c
+++ b/drivers/gpu/drm/msm/msm_fb.c
@@ -24,10 +24,72 @@ struct msm_framebuffer {
static struct drm_framebuffer *msm_framebuffer_init(struct drm_device *dev,
const struct drm_mode_fb_cmd2 *mode_cmd, struct drm_gem_object **bos);
+static int msm_framebuffer_dirtyfb(struct drm_framebuffer *fb,
+ struct drm_file *file_priv, unsigned int flags,
+ unsigned int color, struct drm_clip_rect *clips,
+ unsigned int num_clips)
+{
+ struct msm_drm_private *priv = fb->dev->dev_private;
+ struct drm_modeset_acquire_ctx ctx;
+ struct drm_plane *plane;
+ bool needs_flush = false;
+ int ret = 0;
+
+ /*
+ * When called from ioctl, we are interruptible, but not when called
+ * internally (ie. defio worker)
+ */
+ drm_modeset_acquire_init(&ctx,
+ file_priv ? DRM_MODESET_ACQUIRE_INTERRUPTIBLE : 0);
+
+retry:
+ drm_for_each_plane(plane, fb->dev) {
+ struct drm_plane_state *plane_state;
+ struct drm_crtc *crtc;
+
+ ret = drm_modeset_lock(&plane->mutex, &ctx);
+ if (ret)
+ goto out;
+
+ if (plane->state->fb != fb) {
+ drm_modeset_unlock(&plane->mutex);
+ continue;
+ }
+
+ crtc = plane->state->crtc;
+
+ ret = drm_modeset_lock(&crtc->mutex, &ctx);
+ if (ret)
+ goto out;
+
+ if (priv->kms->funcs->needs_dirtyfb(crtc)) {
+ needs_flush = true;
+ break;
+ }
+ }
+
+out:
+ if (ret == -EDEADLK) {
+ ret = drm_modeset_backoff(&ctx);
+ if (!ret)
+ goto retry;
+ }
+
+ drm_modeset_drop_locks(&ctx);
+ drm_modeset_acquire_fini(&ctx);
+
+ if (needs_flush) {
+ ret = drm_atomic_helper_dirtyfb(fb, file_priv, flags,
+ color, clips, num_clips);
+ }
+
+ return ret;
+}
+
static const struct drm_framebuffer_funcs msm_framebuffer_funcs = {
.create_handle = drm_gem_fb_create_handle,
.destroy = drm_gem_fb_destroy,
- .dirty = drm_atomic_helper_dirtyfb,
+ .dirty = msm_framebuffer_dirtyfb,
};
#ifdef CONFIG_DEBUG_FS
diff --git a/drivers/gpu/drm/msm/msm_kms.h b/drivers/gpu/drm/msm/msm_kms.h
index 2a4f0526cb98..eb870d499d1e 100644
--- a/drivers/gpu/drm/msm/msm_kms.h
+++ b/drivers/gpu/drm/msm/msm_kms.h
@@ -117,6 +117,8 @@ struct msm_kms_funcs {
struct drm_encoder *encoder,
struct drm_encoder *slave_encoder,
bool is_cmd_mode);
+ bool (*needs_dirtyfb)(struct drm_crtc *crtc);
+
/* cleanup: */
void (*destroy)(struct msm_kms *kms);
--
2.34.1
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