This fixes a deadlock inversion when vblank is enabled/disabled by drm. &dev->vblank_time_lock is always taken when the vblank state is toggled, which caused a deadlock when &event->lock was also taken during event_get/put.
Solve the race by requiring that lock to change enable/disable state, and always keeping vblank on the event list. Core drm ignores unwanted vblanks, so extra calls to drm_handle_vblank are harmless.
Signed-off-by: Maarten Lankhorst maarten.lankhorst@canonical.com --- diff --git a/drivers/gpu/drm/nouveau/core/core/event.c b/drivers/gpu/drm/nouveau/core/core/event.c index 7eb81c1..78bff7c 100644 --- a/drivers/gpu/drm/nouveau/core/core/event.c +++ b/drivers/gpu/drm/nouveau/core/core/event.c @@ -23,43 +23,64 @@ #include <core/os.h> #include <core/event.h>
-static void -nouveau_event_put_locked(struct nouveau_event *event, int index, - struct nouveau_eventh *handler) -{ - if (!--event->index[index].refs) { - if (event->disable) - event->disable(event, index); - } - list_del(&handler->head); -} - void nouveau_event_put(struct nouveau_event *event, int index, struct nouveau_eventh *handler) { unsigned long flags;
+ if (index >= event->index_nr) + return; + spin_lock_irqsave(&event->lock, flags); - if (index < event->index_nr) - nouveau_event_put_locked(event, index, handler); + list_del(&handler->head); + + if (event->toggle_lock) + spin_lock(event->toggle_lock); + nouveau_event_disable_locked(event, index, 1); + if (event->toggle_lock) + spin_unlock(event->toggle_lock); + spin_unlock_irqrestore(&event->lock, flags); }
void +nouveau_event_enable_locked(struct nouveau_event *event, int index) +{ + if (index >= event->index_nr) + return; + + if (!event->index[index].refs++ && event->enable) + event->enable(event, index); +} + +void +nouveau_event_disable_locked(struct nouveau_event *event, int index, int refs) +{ + if (index >= event->index_nr) + return; + + event->index[index].refs -= refs; + if (!event->index[index].refs && event->disable) + event->disable(event, index); +} + +void nouveau_event_get(struct nouveau_event *event, int index, struct nouveau_eventh *handler) { unsigned long flags;
+ if (index >= event->index_nr) + return; + spin_lock_irqsave(&event->lock, flags); - if (index < event->index_nr) { - list_add(&handler->head, &event->index[index].list); - if (!event->index[index].refs++) { - if (event->enable) - event->enable(event, index); - } - } + list_add(&handler->head, &event->index[index].list); + if (event->toggle_lock) + spin_lock(event->toggle_lock); + nouveau_event_enable_locked(event, index); + if (event->toggle_lock) + spin_unlock(event->toggle_lock); spin_unlock_irqrestore(&event->lock, flags); }
@@ -68,6 +89,7 @@ nouveau_event_trigger(struct nouveau_event *event, int index) { struct nouveau_eventh *handler, *temp; unsigned long flags; + int refs = 0;
if (index >= event->index_nr) return; @@ -75,9 +97,17 @@ nouveau_event_trigger(struct nouveau_event *event, int index) spin_lock_irqsave(&event->lock, flags); list_for_each_entry_safe(handler, temp, &event->index[index].list, head) { if (handler->func(handler, index) == NVKM_EVENT_DROP) { - nouveau_event_put_locked(event, index, handler); + list_del(&handler->head); + refs++; } } + if (refs) { + if (event->toggle_lock) + spin_lock(event->toggle_lock); + nouveau_event_disable_locked(event, index, refs); + if (event->toggle_lock) + spin_unlock(event->toggle_lock); + } spin_unlock_irqrestore(&event->lock, flags); }
diff --git a/drivers/gpu/drm/nouveau/core/include/core/event.h b/drivers/gpu/drm/nouveau/core/include/core/event.h index 9e09440..b1a6c91 100644 --- a/drivers/gpu/drm/nouveau/core/include/core/event.h +++ b/drivers/gpu/drm/nouveau/core/include/core/event.h @@ -12,6 +12,7 @@ struct nouveau_eventh {
struct nouveau_event { spinlock_t lock; + spinlock_t *toggle_lock;
void *priv; void (*enable)(struct nouveau_event *, int index); @@ -33,4 +34,8 @@ void nouveau_event_get(struct nouveau_event *, int index, void nouveau_event_put(struct nouveau_event *, int index, struct nouveau_eventh *);
+void nouveau_event_enable_locked(struct nouveau_event *event, int index); +void nouveau_event_disable_locked(struct nouveau_event *event, int index, + int refs); + #endif diff --git a/drivers/gpu/drm/nouveau/nouveau_crtc.h b/drivers/gpu/drm/nouveau/nouveau_crtc.h index d1e5890..398baa3 100644 --- a/drivers/gpu/drm/nouveau/nouveau_crtc.h +++ b/drivers/gpu/drm/nouveau/nouveau_crtc.h @@ -29,6 +29,7 @@
struct nouveau_crtc { struct drm_crtc base; + struct nouveau_eventh vblank;
int index;
diff --git a/drivers/gpu/drm/nouveau/nouveau_display.h b/drivers/gpu/drm/nouveau/nouveau_display.h index 1ea3e47..4ba8cb5 100644 --- a/drivers/gpu/drm/nouveau/nouveau_display.h +++ b/drivers/gpu/drm/nouveau/nouveau_display.h @@ -72,6 +72,7 @@ int nouveau_display_dumb_destroy(struct drm_file *, struct drm_device *, u32 handle);
void nouveau_hdmi_mode_set(struct drm_encoder *, struct drm_display_mode *); +int nouveau_drm_vblank_handler(struct nouveau_eventh *event, int head);
#ifdef CONFIG_DRM_NOUVEAU_BACKLIGHT extern int nouveau_backlight_init(struct drm_device *); diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.c b/drivers/gpu/drm/nouveau/nouveau_drm.c index 4bf8dc3..bd301f4 100644 --- a/drivers/gpu/drm/nouveau/nouveau_drm.c +++ b/drivers/gpu/drm/nouveau/nouveau_drm.c @@ -46,6 +46,7 @@ #include "nouveau_pm.h" #include "nouveau_acpi.h" #include "nouveau_bios.h" +#include "nouveau_crtc.h" #include "nouveau_ioctl.h" #include "nouveau_abi16.h" #include "nouveau_fbcon.h" @@ -71,12 +72,13 @@ module_param_named(modeset, nouveau_modeset, int, 0400);
static struct drm_driver driver;
-static int +int nouveau_drm_vblank_handler(struct nouveau_eventh *event, int head) { - struct nouveau_drm *drm = - container_of(event, struct nouveau_drm, vblank[head]); - drm_handle_vblank(drm->dev, head); + struct nouveau_crtc *nv_crtc = + container_of(event, struct nouveau_crtc, vblank); + + drm_handle_vblank(nv_crtc->base.dev, head); return NVKM_EVENT_KEEP; }
@@ -86,11 +88,9 @@ nouveau_drm_vblank_enable(struct drm_device *dev, int head) struct nouveau_drm *drm = nouveau_drm(dev); struct nouveau_disp *pdisp = nouveau_disp(drm->device);
- if (WARN_ON_ONCE(head > ARRAY_SIZE(drm->vblank))) + if (head >= pdisp->vblank->index_nr) return -EIO; - WARN_ON_ONCE(drm->vblank[head].func); - drm->vblank[head].func = nouveau_drm_vblank_handler; - nouveau_event_get(pdisp->vblank, head, &drm->vblank[head]); + nouveau_event_enable_locked(pdisp->vblank, head); return 0; }
@@ -99,11 +99,9 @@ nouveau_drm_vblank_disable(struct drm_device *dev, int head) { struct nouveau_drm *drm = nouveau_drm(dev); struct nouveau_disp *pdisp = nouveau_disp(drm->device); - if (drm->vblank[head].func) - nouveau_event_put(pdisp->vblank, head, &drm->vblank[head]); - else - WARN_ON_ONCE(1); - drm->vblank[head].func = NULL; + + if (head < pdisp->vblank->index_nr) + nouveau_event_disable_locked(pdisp->vblank, head, 1); }
static u64 diff --git a/drivers/gpu/drm/nouveau/nouveau_drm.h b/drivers/gpu/drm/nouveau/nouveau_drm.h index 41ff7e0..0d0ba3b 100644 --- a/drivers/gpu/drm/nouveau/nouveau_drm.h +++ b/drivers/gpu/drm/nouveau/nouveau_drm.h @@ -125,7 +125,6 @@ struct nouveau_drm { struct nvbios vbios; struct nouveau_display *display; struct backlight_device *backlight; - struct nouveau_eventh vblank[4];
/* power management */ struct nouveau_pm *pm; diff --git a/drivers/gpu/drm/nouveau/nv50_display.c b/drivers/gpu/drm/nouveau/nv50_display.c index 007731d..738d7a2 100644 --- a/drivers/gpu/drm/nouveau/nv50_display.c +++ b/drivers/gpu/drm/nouveau/nv50_display.c @@ -39,6 +39,7 @@ #include <core/client.h> #include <core/gpuobj.h> #include <core/class.h> +#include <engine/disp.h>
#include <subdev/timer.h> #include <subdev/bar.h> @@ -1280,15 +1281,21 @@ nv50_crtc_gamma_set(struct drm_crtc *crtc, u16 *r, u16 *g, u16 *b, static void nv50_crtc_destroy(struct drm_crtc *crtc) { + struct nouveau_event *event = nouveau_disp(nouveau_dev(crtc->dev))->vblank; struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc); struct nv50_disp *disp = nv50_disp(crtc->dev); struct nv50_head *head = nv50_head(crtc); + unsigned long flags;
nv50_dmac_destroy(disp->core, &head->ovly.base); nv50_pioc_destroy(disp->core, &head->oimm.base); nv50_dmac_destroy(disp->core, &head->sync.base); nv50_pioc_destroy(disp->core, &head->curs.base);
+ spin_lock_irqsave(&event->lock, flags); + list_del(&nv_crtc->vblank.head); + spin_unlock_irqrestore(&event->lock, flags); + /*XXX: this shouldn't be necessary, but the core doesn't call * disconnect() during the cleanup paths */ @@ -1344,10 +1351,12 @@ nv50_cursor_set_offset(struct nouveau_crtc *nv_crtc, uint32_t offset) static int nv50_crtc_create(struct drm_device *dev, struct nouveau_object *core, int index) { + struct nouveau_event *event = nouveau_disp(nouveau_dev(dev))->vblank; struct nv50_disp *disp = nv50_disp(dev); struct nv50_head *head; struct drm_crtc *crtc; int ret, i; + unsigned long flags;
head = kzalloc(sizeof(*head), GFP_KERNEL); if (!head) @@ -1372,6 +1381,12 @@ nv50_crtc_create(struct drm_device *dev, struct nouveau_object *core, int index) drm_crtc_helper_add(crtc, &nv50_crtc_hfunc); drm_mode_crtc_set_gamma_size(crtc, 256);
+ spin_lock_irqsave(&event->lock, flags); + event->toggle_lock = &dev->vblank_time_lock; + head->base.vblank.func = nouveau_drm_vblank_handler; + list_add(&head->base.vblank.head, &event->index[index].list); + spin_unlock_irqrestore(&event->lock, flags); + ret = nouveau_bo_new(dev, 8192, 0x100, TTM_PL_FLAG_VRAM, 0, 0x0000, NULL, NULL, &head->base.lut.nvbo); if (!ret) {