From 07e769ba3d82ac614725c81c512a8b54d33f2c9e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ma=C3=ADra=20Canal?= Date: Sat, 18 Jul 2026 10:44:37 -0300 Subject: [PATCH] drm/v3d: Idle AXI transactions before disabling the clock on suspend MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Currently, v3d_power_suspend() removes the GPU clock without first quiescing the GPU's memory interface (AXI). If the clock is cut while the core still has outstanding AXI transactions in flight, the hardware is frozen mid-transaction. That corrupted state survives the power cycle, and the first job submitted after the next resume will cause a GPU hang accompanied by an L2T "pte invalid" MMU fault. The hardware already provides a safe-powerdown sequence for this: request the GMP to stop and wait for outstanding reads/writes to drain (v3d_idle_axi()), plus the GCA safe shutdown on pre-4.1 HW (v3d_idle_gca()). The driver implements both, but the runtime PM support added later never invoked them when powering the GPU down. Perform the safe-powerdown sequence in v3d_power_suspend() before disabling the clock, while the core is still powered. Link: https://github.com/raspberrypi/linux/issues/7443 Link: https://github.com/raspberrypi/linux/issues/7488 Fixes: 458f2a712ab4 ("drm/v3d: Introduce Runtime Power Management") Reviewed-by: Iago Toral Quiroga Link: https://patch.msgid.link/20260718-v3d-pm-axi-transactions-v1-2-4ecd7729ed70@igalia.com Signed-off-by: Maíra Canal --- drivers/gpu/drm/v3d/v3d_drv.h | 2 ++ drivers/gpu/drm/v3d/v3d_gem.c | 4 ++-- drivers/gpu/drm/v3d/v3d_power.c | 7 +++++++ 3 files changed, 11 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/v3d/v3d_drv.h b/drivers/gpu/drm/v3d/v3d_drv.h index 4ebe175a8c6b..423bcfe331a0 100644 --- a/drivers/gpu/drm/v3d/v3d_drv.h +++ b/drivers/gpu/drm/v3d/v3d_drv.h @@ -571,6 +571,8 @@ extern bool super_pages; void v3d_init_hw_state(struct v3d_dev *v3d); int v3d_gem_init(struct drm_device *dev); void v3d_gem_destroy(struct drm_device *dev); +void v3d_idle_axi(struct v3d_dev *v3d, int core); +void v3d_idle_gca(struct v3d_dev *v3d); void v3d_reset_sms(struct v3d_dev *v3d); void v3d_reset(struct v3d_dev *v3d); void v3d_invalidate_caches(struct v3d_dev *v3d); diff --git a/drivers/gpu/drm/v3d/v3d_gem.c b/drivers/gpu/drm/v3d/v3d_gem.c index bb0eec870794..23a0db9575a5 100644 --- a/drivers/gpu/drm/v3d/v3d_gem.c +++ b/drivers/gpu/drm/v3d/v3d_gem.c @@ -36,7 +36,7 @@ v3d_init_core(struct v3d_dev *v3d, int core) V3D_CORE_WRITE(core, V3D_CTL_L2TFLEND, ~0); } -static void +void v3d_idle_axi(struct v3d_dev *v3d, int core) { if (v3d->ver >= V3D_GEN_71) { @@ -61,7 +61,7 @@ v3d_idle_axi(struct v3d_dev *v3d, int core) } } -static void +void v3d_idle_gca(struct v3d_dev *v3d) { if (v3d->ver >= V3D_GEN_41) diff --git a/drivers/gpu/drm/v3d/v3d_power.c b/drivers/gpu/drm/v3d/v3d_power.c index f7df6393d38f..c53146316079 100644 --- a/drivers/gpu/drm/v3d/v3d_power.c +++ b/drivers/gpu/drm/v3d/v3d_power.c @@ -54,8 +54,15 @@ int v3d_power_suspend(struct device *dev) v3d_clean_caches(v3d); + /* Wait until V3D has no active or pending AXI transactions. */ + v3d_idle_axi(v3d, 0); + v3d_idle_gca(v3d); + ret = v3d_suspend_sms(v3d); if (ret) { + /* Staying active: undo the GMP STOP_REQ from v3d_idle_axi(). */ + V3D_WRITE(V3D_GMP_CFG(v3d->ver), + V3D_READ(V3D_GMP_CFG(v3d->ver)) & ~V3D_GMP_CFG_STOP_REQ); v3d_irq_enable(v3d); return ret; }