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.lankho...@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) {
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