[PATCH v6 04/13] drm/imx: dc-crtc: Disable at boot
From: Liu Ying <victor.liu@nxp.com>
Date: 2026-09-04 07:54:04
Also in:
dri-devel, imx, linux-devicetree, lkml
Subsystem:
drm drivers, drm drivers and misc gpu patches, drm drivers for freescale imx8 display controller, the rest · Maintainers:
David Airlie, Simona Vetter, Maarten Lankhorst, Maxime Ripard, Thomas Zimmermann, Liu Ying, Linus Torvalds
CRTC(s) could still be running after the DRM device is unplugged by
calling drm_dev_unplug(), because the CRTC disablement logic is
protected and bypassed by the drm_dev_enter()/drm_dev_exit() pair.
Hence, Pixel Engine's AXI clock use count(managed by Pixel Engine
driver's runtime PM) and pixel clock use count could be inbalanced
after removing and re-installing the driver module. To fix this,
add a helper dc_crtc_disable_at_boot() and call it to properly
disable all CRTCs before advertising DRM device to user-space by
calling drm_dev_register().
Fixes: 711a3b878366 ("drm/imx: Add i.MX8qxp Display Controller KMS")
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Liu Ying <victor.liu@nxp.com>
---
v6:
- Rebase onto the latest drm-misc-next and resolve conflicts.
v3:
- Collect Frank's R-b tag.
---
drivers/gpu/drm/imx/dc/dc-crtc.c | 55 +++++++++++++++++++++++++++++++++-------
drivers/gpu/drm/imx/dc/dc-drv.c | 5 ++++
drivers/gpu/drm/imx/dc/dc-drv.h | 3 +++
3 files changed, 54 insertions(+), 9 deletions(-)
diff --git a/drivers/gpu/drm/imx/dc/dc-crtc.c b/drivers/gpu/drm/imx/dc/dc-crtc.c
index 0d64186a9901..1a537cf88daf 100644
--- a/drivers/gpu/drm/imx/dc/dc-crtc.c
+++ b/drivers/gpu/drm/imx/dc/dc-crtc.c@@ -293,23 +293,29 @@ dc_crtc_atomic_enable(struct drm_crtc *crtc, struct drm_atomic_commit *state) dc_crtc_queue_state_event(new_crtc_state); } -static void -dc_crtc_atomic_disable(struct drm_crtc *crtc, struct drm_atomic_commit *state) +static inline void __dc_crtc_disable_fg(struct drm_crtc *crtc) { - struct drm_crtc_state *new_crtc_state = - drm_atomic_get_new_crtc_state(state, crtc); - struct dc_drm_device *dc_drm = to_dc_drm_device(crtc->dev); struct dc_crtc *dc_crtc = to_dc_crtc(crtc); - int idx; - - if (!drm_dev_enter(crtc->dev, &idx)) - goto out; enable_irq(dc_crtc->irq_dec_seqcomplete); dc_fg_disable(dc_crtc->fg); DC_CRTC_WAIT_FOR_COMPLETION_TIMEOUT(dec_seqcomplete_done); disable_irq(dc_crtc->irq_dec_seqcomplete); +} +static void +dc_crtc_atomic_disable(struct drm_crtc *crtc, struct drm_atomic_commit *state) +{ + struct drm_crtc_state *new_crtc_state = + drm_atomic_get_new_crtc_state(state, crtc); + struct dc_drm_device *dc_drm = to_dc_drm_device(crtc->dev); + struct dc_crtc *dc_crtc = to_dc_crtc(crtc); + int idx; + + if (!drm_dev_enter(crtc->dev, &idx)) + goto out; + + __dc_crtc_disable_fg(crtc); dc_fg_disable_clock(dc_crtc->fg); /* request pixel engine power-off as plane is off too */
@@ -331,6 +337,37 @@ dc_crtc_atomic_disable(struct drm_crtc *crtc, struct drm_atomic_commit *state) spin_unlock_irq(&crtc->dev->event_lock); } +void dc_crtc_disable_at_boot(struct drm_crtc *crtc) +{ + struct dc_drm_device *dc_drm = to_dc_drm_device(crtc->dev); + struct dc_crtc *dc_crtc = to_dc_crtc(crtc); + int ret; + + ret = pm_runtime_resume_and_get(dc_crtc->de->dev); + if (ret < 0) { + dc_crtc_err(crtc, "failed to get DC display engine RPM: %d\n", + ret); + return; + } + + if (!dc_fg_wait_for_frame_index_moving(dc_crtc->fg)) { + dc_crtc_dbg(crtc, "FrameGen frame index isn't moving\n"); + goto out; + } + + dc_crtc_dbg(crtc, "disabling at boot\n"); + __dc_crtc_disable_fg(crtc); + dc_fg_disable_clock(dc_crtc->fg); + + if (!dc_drm->pe_clk_axi_disabled) { + clk_disable_unprepare(dc_drm->pe->clk_axi); + dc_drm->pe_clk_axi_disabled = true; + } + +out: + pm_runtime_put(dc_crtc->de->dev); +} + static bool dc_crtc_get_scanout_position(struct drm_crtc *crtc, bool in_vblank_irq, int *vpos, int *hpos,
diff --git a/drivers/gpu/drm/imx/dc/dc-drv.c b/drivers/gpu/drm/imx/dc/dc-drv.c
index 13795a2ad735..c051a17c3643 100644
--- a/drivers/gpu/drm/imx/dc/dc-drv.c
+++ b/drivers/gpu/drm/imx/dc/dc-drv.c@@ -16,6 +16,7 @@ #include <drm/clients/drm_client_setup.h> #include <drm/drm_atomic_helper.h> +#include <drm/drm_crtc.h> #include <drm/drm_drv.h> #include <drm/drm_fbdev_dma.h> #include <drm/drm_fourcc.h>
@@ -95,6 +96,7 @@ static int dc_drm_bind(struct device *dev) struct dc_priv *priv = dev_get_drvdata(dev); struct dc_drm_device *dc_drm; struct drm_device *drm; + struct drm_crtc *crtc; int ret; dc_drm = devm_drm_dev_alloc(dev, &dc_drm_driver, struct dc_drm_device,
@@ -117,6 +119,9 @@ static int dc_drm_bind(struct device *dev) if (ret) return ret; + drm_for_each_crtc(crtc, drm) + dc_crtc_disable_at_boot(crtc); + ret = drm_dev_register(drm, 0); if (ret) { dev_err(dev, "failed to register drm device: %d\n", ret);
diff --git a/drivers/gpu/drm/imx/dc/dc-drv.h b/drivers/gpu/drm/imx/dc/dc-drv.h
index eb61b8c76269..68e99ba7cedb 100644
--- a/drivers/gpu/drm/imx/dc/dc-drv.h
+++ b/drivers/gpu/drm/imx/dc/dc-drv.h@@ -50,6 +50,8 @@ struct dc_drm_device { struct dc_pe *pe; /** @tc: tcon list */ struct dc_tc *tc[DC_DISPLAYS]; + /** @pe_clk_axi_disabled: disablement flag at boot */ + bool pe_clk_axi_disabled; }; struct dc_subdev_info {
@@ -96,6 +98,7 @@ static inline int dc_subdev_get_id(const struct dc_subdev_info *info, return -EINVAL; } +void dc_crtc_disable_at_boot(struct drm_crtc *crtc); void dc_de_post_bind(struct dc_drm_device *dc_drm); void dc_pe_post_bind(struct dc_drm_device *dc_drm);
--
2.43.0