[PATCH RFC 09/10] drm/msm/dsi: separate host link enable from video stream enable
COOLING5d
From: YİĞİTCAN KAVAKLI via B4 Relay <devnull+kavakliyigitcan.gmail.com@kernel.org>
Date: 2026-09-11 08:51:28
Also in:
b4-sent, dri-devel, linux-arm-msm, linux-devicetree, linux-fbdev, linux-leds, lkml
Subsystem:
drm driver for qualcomm display hardware, drm drivers, the rest · Maintainers:
Rob Clark, Dmitry Baryshkov, David Airlie, Simona Vetter, Linus Torvalds
From: YİĞİTCAN KAVAKLI <redacted> In video mode DSI displays, enabling the host previously engaged the hardware video engine immediately during atomic_pre_enable. When panel prepare routines transmit initial DCS sleep-out and setup commands, concurrent active video transmission causes DMA timeouts (-110). Keep the DSI host in command mode during atomic_pre_enable to permit clean panel preparation, and start video streaming in atomic_enable after the panel has completed initialization. Signed-off-by: YİĞİTCAN KAVAKLI <redacted> --- drivers/gpu/drm/msm/dsi/dsi.h | 1 + drivers/gpu/drm/msm/dsi/dsi_host.c | 23 ++++++++++++----------- drivers/gpu/drm/msm/dsi/dsi_manager.c | 20 ++++++++++++++++++++ 3 files changed, 33 insertions(+), 11 deletions(-)
diff --git a/drivers/gpu/drm/msm/dsi/dsi.h b/drivers/gpu/drm/msm/dsi/dsi.h
index 93c028a122f3a59b1632da76472e0a3e781c6ae8..cfb2b51cae0a9227fbe88ecc5291ac1a9f82a5ce 100644
--- a/drivers/gpu/drm/msm/dsi/dsi.h
+++ b/drivers/gpu/drm/msm/dsi/dsi.h@@ -69,6 +69,7 @@ int msm_dsi_host_cmd_rx(struct mipi_dsi_host *host, void msm_dsi_host_cmd_xfer_commit(struct mipi_dsi_host *host, u32 dma_base, u32 len); int msm_dsi_host_enable(struct mipi_dsi_host *host); +void msm_dsi_host_enable_video(struct mipi_dsi_host *host); int msm_dsi_host_disable(struct mipi_dsi_host *host); void msm_dsi_host_enable_irq(struct mipi_dsi_host *host); void msm_dsi_host_disable_irq(struct mipi_dsi_host *host);
diff --git a/drivers/gpu/drm/msm/dsi/dsi_host.c b/drivers/gpu/drm/msm/dsi/dsi_host.c
index b9e2867d435a3ad8b6db6b57c440bbd827180b6e..b2702f772ee195b2758433d98d0f071e3f55955e 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_host.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_host.c@@ -2438,22 +2438,23 @@ int msm_dsi_host_enable(struct mipi_dsi_host *host) { struct msm_dsi_host *msm_host = to_msm_dsi_host(host); - dsi_op_mode_config(msm_host, - !!(msm_host->mode_flags & MIPI_DSI_MODE_VIDEO), true); - - /* TODO: clock should be turned off for command mode, - * and only turned on before MDP START. - * This part of code should be enabled once mdp driver support it. - */ - /* if (msm_panel->mode == MSM_DSI_CMD_MODE) { - * dsi_link_clk_disable(msm_host); - * pm_runtime_put(&msm_host->pdev->dev); - * } + /* Keep DSI host in command mode (VID_MODE_EN = 0) during panel init + * to allow clean DCS communication without premature video engine startup. */ + dsi_op_mode_config(msm_host, false, true); + msm_host->enabled = true; return 0; } +void msm_dsi_host_enable_video(struct mipi_dsi_host *host) +{ + struct msm_dsi_host *msm_host = to_msm_dsi_host(host); + + if (msm_host->mode_flags & MIPI_DSI_MODE_VIDEO) + dsi_op_mode_config(msm_host, true, true); +} + int msm_dsi_host_disable(struct mipi_dsi_host *host) { struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
diff --git a/drivers/gpu/drm/msm/dsi/dsi_manager.c b/drivers/gpu/drm/msm/dsi/dsi_manager.c
index 959daa88b1d022da5f552bb21ca7c04006524fa4..9e3f125ec4ea8e3fae50c8226e67b4106c01dc76 100644
--- a/drivers/gpu/drm/msm/dsi/dsi_manager.c
+++ b/drivers/gpu/drm/msm/dsi/dsi_manager.c@@ -446,12 +446,32 @@ static int dsi_mgr_bridge_attach(struct drm_bridge *bridge, bridge, flags); } +static void dsi_mgr_bridge_enable(struct drm_bridge *bridge, + struct drm_atomic_commit *commit) +{ + int id = dsi_mgr_bridge_get_id(bridge); + struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id); + struct msm_dsi *msm_dsi1 = dsi_mgr_get_dsi(DSI_1); + struct mipi_dsi_host *host = msm_dsi->host; + bool is_bonded_dsi = IS_BONDED_DSI(); + + DBG("id=%d", id); + + if (is_bonded_dsi && !IS_MASTER_DSI_LINK(id)) + return; + + msm_dsi_host_enable_video(host); + if (is_bonded_dsi && msm_dsi1) + msm_dsi_host_enable_video(msm_dsi1->host); +} + static const struct drm_bridge_funcs dsi_mgr_bridge_funcs = { .atomic_create_state = drm_atomic_helper_bridge_create_state, .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state, .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state, .attach = dsi_mgr_bridge_attach, .atomic_pre_enable = dsi_mgr_bridge_pre_enable, + .atomic_enable = dsi_mgr_bridge_enable, .atomic_post_disable = dsi_mgr_bridge_post_disable, .mode_set = dsi_mgr_bridge_mode_set, .mode_valid = dsi_mgr_bridge_mode_valid,
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2.47.3