The patch below does not apply to the 5.11-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From ea3b4242bc9ca197762119382b37e125815bd67f Mon Sep 17 00:00:00 2001
From: Qingqing Zhuo qingqing.zhuo@amd.com Date: Tue, 9 Feb 2021 16:36:41 -0500 Subject: [PATCH] drm/amd/display: Fix system hang after multiple hotplugs (v3)
[Why] mutex_lock() was introduced in dm_disable_vblank(), which could be called in an IRQ context. Waiting in IRQ would cause issues like kernel lockup, etc.
[How] Handle code that requires mutex lock on a different thread.
v2: squash in compilation fix without CONFIG_DRM_AMD_DC_DCN (Alex) v3: squash in warning fix (Wei)
Signed-off-by: Qingqing Zhuo qingqing.zhuo@amd.com Acked-by: Bindu Ramamurthy bindu.r@amd.com Tested-by: Daniel Wheeler daniel.wheeler@amd.com Signed-off-by: Alex Deucher alexander.deucher@amd.com Cc: stable@vger.kernel.org
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c index 344404c4ac75..3e1fd1e7d09f 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.c @@ -937,7 +937,49 @@ static void mmhub_read_system_context(struct amdgpu_device *adev, struct dc_phy_
} #endif +#if defined(CONFIG_DRM_AMD_DC_DCN) +static void event_mall_stutter(struct work_struct *work) +{ + + struct vblank_workqueue *vblank_work = container_of(work, struct vblank_workqueue, mall_work); + struct amdgpu_display_manager *dm = vblank_work->dm; + + mutex_lock(&dm->dc_lock); + + if (vblank_work->enable) + dm->active_vblank_irq_count++; + else + dm->active_vblank_irq_count--; + + + dc_allow_idle_optimizations( + dm->dc, dm->active_vblank_irq_count == 0 ? true : false); + + DRM_DEBUG_DRIVER("Allow idle optimizations (MALL): %d\n", dm->active_vblank_irq_count == 0); + + + mutex_unlock(&dm->dc_lock); +} + +static struct vblank_workqueue *vblank_create_workqueue(struct amdgpu_device *adev, struct dc *dc) +{ + + int max_caps = dc->caps.max_links; + struct vblank_workqueue *vblank_work; + int i = 0; + + vblank_work = kcalloc(max_caps, sizeof(*vblank_work), GFP_KERNEL); + if (ZERO_OR_NULL_PTR(vblank_work)) { + kfree(vblank_work); + return NULL; + }
+ for (i = 0; i < max_caps; i++) + INIT_WORK(&vblank_work[i].mall_work, event_mall_stutter); + + return vblank_work; +} +#endif static int amdgpu_dm_init(struct amdgpu_device *adev) { struct dc_init_data init_data; @@ -957,6 +999,9 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
mutex_init(&adev->dm.dc_lock); mutex_init(&adev->dm.audio_lock); +#if defined(CONFIG_DRM_AMD_DC_DCN) + spin_lock_init(&adev->dm.vblank_lock); +#endif
if(amdgpu_dm_irq_init(adev)) { DRM_ERROR("amdgpu: failed to initialize DM IRQ support.\n"); @@ -1071,6 +1116,17 @@ static int amdgpu_dm_init(struct amdgpu_device *adev)
amdgpu_dm_init_color_mod();
+#if defined(CONFIG_DRM_AMD_DC_DCN) + if (adev->dm.dc->caps.max_links > 0) { + adev->dm.vblank_workqueue = vblank_create_workqueue(adev, adev->dm.dc); + + if (!adev->dm.vblank_workqueue) + DRM_ERROR("amdgpu: failed to initialize vblank_workqueue.\n"); + else + DRM_DEBUG_DRIVER("amdgpu: vblank_workqueue init done %p.\n", adev->dm.vblank_workqueue); + } +#endif + #ifdef CONFIG_DRM_AMD_DC_HDCP if (adev->dm.dc->caps.max_links > 0 && adev->asic_type >= CHIP_RAVEN) { adev->dm.hdcp_workqueue = hdcp_create_workqueue(adev, &init_params.cp_psp, adev->dm.dc); @@ -5375,7 +5431,10 @@ static inline int dm_set_vblank(struct drm_crtc *crtc, bool enable) struct amdgpu_crtc *acrtc = to_amdgpu_crtc(crtc); struct amdgpu_device *adev = drm_to_adev(crtc->dev); struct dm_crtc_state *acrtc_state = to_dm_crtc_state(crtc->state); +#if defined(CONFIG_DRM_AMD_DC_DCN) struct amdgpu_display_manager *dm = &adev->dm; + unsigned long flags; +#endif int rc = 0;
if (enable) { @@ -5398,22 +5457,15 @@ static inline int dm_set_vblank(struct drm_crtc *crtc, bool enable) if (amdgpu_in_reset(adev)) return 0;
- mutex_lock(&dm->dc_lock); - - if (enable) - dm->active_vblank_irq_count++; - else - dm->active_vblank_irq_count--; - #if defined(CONFIG_DRM_AMD_DC_DCN) - dc_allow_idle_optimizations( - adev->dm.dc, dm->active_vblank_irq_count == 0 ? true : false); - - DRM_DEBUG_DRIVER("Allow idle optimizations (MALL): %d\n", dm->active_vblank_irq_count == 0); + spin_lock_irqsave(&dm->vblank_lock, flags); + dm->vblank_workqueue->dm = dm; + dm->vblank_workqueue->otg_inst = acrtc->otg_inst; + dm->vblank_workqueue->enable = enable; + spin_unlock_irqrestore(&dm->vblank_lock, flags); + schedule_work(&dm->vblank_workqueue->mall_work); #endif
- mutex_unlock(&dm->dc_lock); - return 0; }
diff --git a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h index f72930c36c22..8bfe901cf237 100644 --- a/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h +++ b/drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h @@ -92,6 +92,20 @@ struct dm_compressor_info { uint64_t gpu_addr; };
+/** + * struct vblank_workqueue - Works to be executed in a separate thread during vblank + * @mall_work: work for mall stutter + * @dm: amdgpu display manager device + * @otg_inst: otg instance of which vblank is being set + * @enable: true if enable vblank + */ +struct vblank_workqueue { + struct work_struct mall_work; + struct amdgpu_display_manager *dm; + int otg_inst; + bool enable; +}; + /** * struct amdgpu_dm_backlight_caps - Information about backlight * @@ -243,6 +257,15 @@ struct amdgpu_display_manager { */ struct mutex audio_lock;
+ /** + * @vblank_work_lock: + * + * Guards access to deferred vblank work state. + */ +#if defined(CONFIG_DRM_AMD_DC_DCN) + spinlock_t vblank_lock; +#endif + /** * @audio_component: * @@ -321,6 +344,10 @@ struct amdgpu_display_manager { struct hdcp_workqueue *hdcp_workqueue; #endif
+#if defined(CONFIG_DRM_AMD_DC_DCN) + struct vblank_workqueue *vblank_workqueue; +#endif + struct drm_atomic_state *cached_state; struct dc_state *cached_dc_state;