Re: [PATCH v4 27/39] drm/msm/dp: replace power_on with active_stream_cnt for dp_display
From: Yongxing Mou
Date: Mon Jun 15 2026 - 04:50:34 EST
On 4/12/2026 8:11 AM, Dmitry Baryshkov wrote:
On Fri, Apr 10, 2026 at 05:34:02PM +0800, Yongxing Mou wrote:I’ve renamed the function to msm_dp_display_prepare_link, which looks better. We’re still in atomic_enable().
From: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
For DP MST, the link clock and power domain resources stay on until
both streams have been disabled OR we receive hotplug. Introduce an
active_stream_cnt to track the number of active streams and necessary
state handling. Replace the power_on variable with active_stream_cnt
as power_on boolean works only for a single stream.
Signed-off-by: Abhinav Kumar <quic_abhinavk@xxxxxxxxxxx>
Signed-off-by: Yongxing Mou <yongxing.mou@xxxxxxxxxxxxxxxx>
---
drivers/gpu/drm/msm/dp/dp_audio.c | 2 +-
drivers/gpu/drm/msm/dp/dp_display.c | 38 +++++++++++++++++++------------------
drivers/gpu/drm/msm/dp/dp_display.h | 2 +-
3 files changed, 22 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/msm/dp/dp_audio.c b/drivers/gpu/drm/msm/dp/dp_audio.c
index 41018e82efa1..035e230201fd 100644
--- a/drivers/gpu/drm/msm/dp/dp_audio.c
+++ b/drivers/gpu/drm/msm/dp/dp_audio.c
@@ -284,7 +284,7 @@ int msm_dp_audio_prepare(struct drm_bridge *bridge,
* such cases check for connection status and bail out if not
* connected.
*/
- if (!msm_dp_display->power_on) {
+ if (!msm_dp_display->active_stream_cnt) {
rc = -EINVAL;
goto end;
}
diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c
index 33d8539afee7..e6ecbb3a688e 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.c
+++ b/drivers/gpu/drm/msm/dp/dp_display.c
@@ -657,15 +657,15 @@ int msm_dp_display_prepare(struct msm_dp *msm_dp_display)
if (dp->link->sink_count == 0)
return rc;
- if (!msm_dp_display->power_on) {
+ if (!msm_dp_display->active_stream_cnt) {
Okay, I'm now being lost between the names. When is prepare being
called? Is it still part of the atomic_enable()? Or atomic_pre_enable()?
Got it..I will update the commit message to explain why this change is needed. Under MST, preparing the link only needs to be done once by the first stream.msm_dp_display_host_phy_init(dp);
force_link_train = true;
- }
- rc = msm_dp_ctrl_on_link(dp->ctrl, msm_dp_display->mst_active);
- if (rc)
- DRM_ERROR("Failed link training (rc=%d)\n", rc);
- // TODO: schedule drm_connector_set_link_status_property()
+ rc = msm_dp_ctrl_on_link(dp->ctrl, msm_dp_display->mst_active);
+ if (rc)
+ DRM_ERROR("Failed link training (rc=%d)\n", rc);
+ // TODO: schedule drm_connector_set_link_status_property()
+ }
Again, this more than the scope of the commit message.
return msm_dp_ctrl_prepare_stream_on(dp->ctrl, force_link_train);
}
@@ -674,18 +674,12 @@ static int msm_dp_display_enable(struct msm_dp_display_private *dp,
struct msm_dp_panel *msm_dp_panel)
{
int rc = 0;
- struct msm_dp *msm_dp_display = &dp->msm_dp_display;
drm_dbg_dp(dp->drm_dev, "sink_count=%d\n", dp->link->sink_count);
- if (msm_dp_display->power_on) {
- drm_dbg_dp(dp->drm_dev, "Link already setup, return\n");
- return 0;
- }
rc = msm_dp_ctrl_on_stream(dp->ctrl, msm_dp_panel);
- if (!rc)
- msm_dp_display->power_on = true;
+ dp->msm_dp_display.active_stream_cnt++;
return rc;
}
@@ -731,16 +725,14 @@ static void msm_dp_display_audio_notify_disable(struct msm_dp_display_private *d
static int msm_dp_display_disable(struct msm_dp_display_private *dp,
struct msm_dp_panel *msm_dp_panel)
{
- struct msm_dp *msm_dp_display = &dp->msm_dp_display;
-
- if (!msm_dp_display->power_on)
+ if (!dp->msm_dp_display.active_stream_cnt)
return 0;
msm_dp_panel_disable_vsc_sdp(msm_dp_panel);
msm_dp_ctrl_off_pixel_clk(dp->ctrl, msm_dp_panel->stream_id);
- msm_dp_display->power_on = false;
+ dp->msm_dp_display.active_stream_cnt--;
drm_dbg_dp(dp->drm_dev, "sink count: %d\n", dp->link->sink_count);
return 0;
@@ -876,7 +868,7 @@ void msm_dp_snapshot(struct msm_disp_state *disp_state, struct msm_dp *dp)
* power_on status before dumping DP registers to avoid crash due
* to unclocked access
*/
- if (!dp->power_on)
+ if (!dp->active_stream_cnt)
return;
msm_disp_snapshot_add_block(disp_state, msm_dp_display->ahb_len,
@@ -1559,6 +1551,11 @@ void msm_dp_display_disable_helper(struct msm_dp *msm_dp_display,
dp = container_of(msm_dp_display, struct msm_dp_display_private, msm_dp_display);
+ if (!msm_dp_display->active_stream_cnt) {
+ drm_dbg_dp(dp->drm_dev, "no active streams\n");
+ return;
+ }
+
msm_dp_ctrl_push_idle(dp->ctrl, msm_dp_panel);
msm_dp_ctrl_mst_stream_channel_slot_setup(dp->ctrl);
msm_dp_ctrl_mst_send_act(dp->ctrl);
@@ -1579,6 +1576,11 @@ void msm_dp_display_unprepare(struct msm_dp *msm_dp_display)
dp = container_of(msm_dp_display, struct msm_dp_display_private, msm_dp_display);
+ if (msm_dp_display->active_stream_cnt) {
+ drm_dbg_dp(dp->drm_dev, "stream still active, return\n");
+ return;
+ }
+
/* dongle is still connected but sinks are disconnected */
if (dp->link->sink_count == 0)
msm_dp_link_psm_config(dp->link, &dp->panel->link_info, true);
diff --git a/drivers/gpu/drm/msm/dp/dp_display.h b/drivers/gpu/drm/msm/dp/dp_display.h
index 0ede5505be58..2548f67cd441 100644
--- a/drivers/gpu/drm/msm/dp/dp_display.h
+++ b/drivers/gpu/drm/msm/dp/dp_display.h
@@ -18,7 +18,7 @@ struct msm_dp {
struct drm_bridge *next_bridge;
struct drm_bridge *bridge;
bool audio_enabled;
- bool power_on;
+ u32 active_stream_cnt;
bool mst_active;
unsigned int connector_type;
bool is_edp;
--
2.43.0