struct file *filp; /**< File descr of lock holder (0=kernel) */
wait_queue_head_t lock_queue; /**< Queue of blocked processes */
unsigned long lock_time; /**< Time of last lock in jiffies */
+ spinlock_t spinlock;
+ uint32_t kernel_waiters;
+ uint32_t user_waiters;
+ int idle_has_lock;
} drm_lock_data_t;
/**
void (*reclaim_buffers) (struct drm_device * dev, struct file * filp);
void (*reclaim_buffers_locked) (struct drm_device *dev,
struct file *filp);
+ void (*reclaim_buffers_idlelocked) (struct drm_device *dev,
+ struct file * filp);
unsigned long (*get_map_ofs) (drm_map_t * map);
unsigned long (*get_reg_ofs) (struct drm_device * dev);
void (*set_version) (struct drm_device * dev, drm_set_version_t * sv);
unsigned int cmd, unsigned long arg);
extern int drm_unlock(struct inode *inode, struct file *filp,
unsigned int cmd, unsigned long arg);
-extern int drm_lock_take(__volatile__ unsigned int *lock, unsigned int context);
-extern int drm_lock_free(drm_device_t * dev,
- __volatile__ unsigned int *lock, unsigned int context);
+extern int drm_lock_take(drm_lock_data_t *lock_data, unsigned int context);
+extern int drm_lock_free(drm_lock_data_t *lock_data, unsigned int context);
+extern void drm_idlelock_take(drm_lock_data_t *lock_data);
+extern void drm_idlelock_release(drm_lock_data_t *lock_data);
+
+/*
+ * These are exported to drivers so that they can implement fencing using
+ * DMA quiscent + idle. DMA quiescent usually requires the hardware lock.
+ */
+
+extern int drm_i_have_hw_lock(struct file *filp);
+extern int drm_kernel_take_hw_lock(struct file *filp);
/* Buffer management support (drm_bufs.h) */
extern int drm_addbufs_agp(drm_device_t * dev, drm_buf_desc_t * request);
current->pid, (long)old_encode_dev(priv->head->device),
dev->open_count);
- if (priv->lock_count && dev->lock.hw_lock &&
- _DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock) &&
- dev->lock.filp == filp) {
- DRM_DEBUG("File %p released, freeing lock for context %d\n",
- filp, _DRM_LOCKING_CONTEXT(dev->lock.hw_lock->lock));
-
- if (dev->driver->reclaim_buffers_locked)
+ if (dev->driver->reclaim_buffers_locked && dev->lock.hw_lock) {
+ if (drm_i_have_hw_lock(filp)) {
dev->driver->reclaim_buffers_locked(dev, filp);
-
- drm_lock_free(dev, &dev->lock.hw_lock->lock,
- _DRM_LOCKING_CONTEXT(dev->lock.hw_lock->lock));
-
- /* FIXME: may require heavy-handed reset of
- hardware at this point, possibly
- processed via a callback to the X
- server. */
- } else if (dev->driver->reclaim_buffers_locked && priv->lock_count
- && dev->lock.hw_lock) {
- /* The lock is required to reclaim buffers */
- DECLARE_WAITQUEUE(entry, current);
-
- add_wait_queue(&dev->lock.lock_queue, &entry);
- for (;;) {
- __set_current_state(TASK_INTERRUPTIBLE);
- if (!dev->lock.hw_lock) {
- /* Device has been unregistered */
- retcode = -EINTR;
- break;
+ } else {
+ unsigned long _end=jiffies + 3*DRM_HZ;
+ int locked = 0;
+
+ drm_idlelock_take(&dev->lock);
+
+ /*
+ * Wait for a while.
+ */
+
+ do{
+ spin_lock(&dev->lock.spinlock);
+ locked = dev->lock.idle_has_lock;
+ spin_unlock(&dev->lock.spinlock);
+ if (locked)
+ break;
+ schedule();
+ } while (!time_after_eq(jiffies, _end));
+
+ if (!locked) {
+ DRM_ERROR("reclaim_buffers_locked() deadlock. Please rework this\n"
+ "\tdriver to use reclaim_buffers_idlelocked() instead.\n"
+ "\tI will go on reclaiming the buffers anyway.\n");
}
- if (drm_lock_take(&dev->lock.hw_lock->lock,
- DRM_KERNEL_CONTEXT)) {
- dev->lock.filp = filp;
- dev->lock.lock_time = jiffies;
- atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
- break; /* Got lock */
- }
- /* Contention */
- schedule();
- if (signal_pending(current)) {
- retcode = -ERESTARTSYS;
- break;
- }
- }
- __set_current_state(TASK_RUNNING);
- remove_wait_queue(&dev->lock.lock_queue, &entry);
- if (!retcode) {
+
dev->driver->reclaim_buffers_locked(dev, filp);
- drm_lock_free(dev, &dev->lock.hw_lock->lock,
- DRM_KERNEL_CONTEXT);
+ drm_idlelock_release(&dev->lock);
}
}
+ if (dev->driver->reclaim_buffers_idlelocked && dev->lock.hw_lock) {
+
+ drm_idlelock_take(&dev->lock);
+ dev->driver->reclaim_buffers_idlelocked(dev, filp);
+ drm_idlelock_release(&dev->lock);
+
+ }
+
+ if (drm_i_have_hw_lock(filp)) {
+ DRM_DEBUG("File %p released, freeing lock for context %d\n",
+ filp, _DRM_LOCKING_CONTEXT(dev->lock.hw_lock->lock));
+
+ drm_lock_free(&dev->lock,
+ _DRM_LOCKING_CONTEXT(dev->lock.hw_lock->lock));
+ }
+
+
if (drm_core_check_feature(dev, DRIVER_HAVE_DMA) &&
!dev->driver->reclaim_buffers_locked) {
dev->driver->reclaim_buffers(dev, filp);
#include "drmP.h"
-static int drm_lock_transfer(drm_device_t * dev,
- __volatile__ unsigned int *lock,
- unsigned int context);
static int drm_notifier(void *priv);
/**
return -EINVAL;
add_wait_queue(&dev->lock.lock_queue, &entry);
+ spin_lock(&dev->lock.spinlock);
+ dev->lock.user_waiters++;
+ spin_unlock(&dev->lock.spinlock);
for (;;) {
__set_current_state(TASK_INTERRUPTIBLE);
if (!dev->lock.hw_lock) {
ret = -EINTR;
break;
}
- if (drm_lock_take(&dev->lock.hw_lock->lock, lock.context)) {
+ if (drm_lock_take(&dev->lock, lock.context)) {
dev->lock.filp = filp;
dev->lock.lock_time = jiffies;
atomic_inc(&dev->counts[_DRM_STAT_LOCKS]);
break;
}
}
+ spin_lock(&dev->lock.spinlock);
+ dev->lock.user_waiters--;
+ spin_unlock(&dev->lock.spinlock);
__set_current_state(TASK_RUNNING);
remove_wait_queue(&dev->lock.lock_queue, &entry);
- DRM_DEBUG("%d %s\n", lock.context, ret ? "interrupted" : "has lock");
- if (ret)
- return ret;
+ DRM_DEBUG( "%d %s\n", lock.context, ret ? "interrupted" : "has lock" );
+ if (ret) return ret;
sigemptyset(&dev->sigmask);
sigaddset(&dev->sigmask, SIGSTOP);
}
}
- /* dev->driver->kernel_context_switch isn't used by any of the x86
- * drivers but is used by the Sparc driver.
- */
if (dev->driver->kernel_context_switch &&
dev->last_context != lock.context) {
dev->driver->kernel_context_switch(dev, dev->last_context,
lock.context);
}
+
return 0;
}
if (dev->driver->kernel_context_switch_unlock)
dev->driver->kernel_context_switch_unlock(dev);
else {
- drm_lock_transfer(dev, &dev->lock.hw_lock->lock,
- DRM_KERNEL_CONTEXT);
-
- if (drm_lock_free(dev, &dev->lock.hw_lock->lock,
- DRM_KERNEL_CONTEXT)) {
- DRM_ERROR("\n");
+ if (drm_lock_free(&dev->lock,lock.context)) {
+ /* FIXME: Should really bail out here. */
}
}
*
* Attempt to mark the lock as held by the given context, via the \p cmpxchg instruction.
*/
-int drm_lock_take(__volatile__ unsigned int *lock, unsigned int context)
+int drm_lock_take(drm_lock_data_t *lock_data,
+ unsigned int context)
{
unsigned int old, new, prev;
+ volatile unsigned int *lock = &lock_data->hw_lock->lock;
+ spin_lock(&lock_data->spinlock);
do {
old = *lock;
if (old & _DRM_LOCK_HELD)
new = old | _DRM_LOCK_CONT;
- else
- new = context | _DRM_LOCK_HELD;
+ else {
+ new = context | _DRM_LOCK_HELD |
+ ((lock_data->user_waiters + lock_data->kernel_waiters > 1) ?
+ _DRM_LOCK_CONT : 0);
+ }
prev = cmpxchg(lock, old, new);
} while (prev != old);
+ spin_unlock(&lock_data->spinlock);
+
if (_DRM_LOCKING_CONTEXT(old) == context) {
if (old & _DRM_LOCK_HELD) {
if (context != DRM_KERNEL_CONTEXT) {
return 0;
}
}
- if (new == (context | _DRM_LOCK_HELD)) {
+
+ if ((_DRM_LOCKING_CONTEXT(new)) == context && (new & _DRM_LOCK_HELD)) {
/* Have lock */
return 1;
}
* Resets the lock file pointer.
* Marks the lock as held by the given context, via the \p cmpxchg instruction.
*/
-static int drm_lock_transfer(drm_device_t * dev,
- __volatile__ unsigned int *lock,
+static int drm_lock_transfer(drm_lock_data_t *lock_data,
unsigned int context)
{
unsigned int old, new, prev;
+ volatile unsigned int *lock = &lock_data->hw_lock->lock;
- dev->lock.filp = NULL;
+ lock_data->filp = NULL;
do {
old = *lock;
new = context | _DRM_LOCK_HELD;
* Marks the lock as not held, via the \p cmpxchg instruction. Wakes any task
* waiting on the lock queue.
*/
-int drm_lock_free(drm_device_t * dev,
- __volatile__ unsigned int *lock, unsigned int context)
+int drm_lock_free(drm_lock_data_t *lock_data, unsigned int context)
{
unsigned int old, new, prev;
+ volatile unsigned int *lock = &lock_data->hw_lock->lock;
+
+ spin_lock(&lock_data->spinlock);
+ if (lock_data->kernel_waiters != 0) {
+ drm_lock_transfer(lock_data, 0);
+ lock_data->idle_has_lock = 1;
+ spin_unlock(&lock_data->spinlock);
+ return 1;
+ }
+ spin_unlock(&lock_data->spinlock);
- dev->lock.filp = NULL;
do {
old = *lock;
- new = 0;
+ new = _DRM_LOCKING_CONTEXT(old);
prev = cmpxchg(lock, old, new);
} while (prev != old);
+
if (_DRM_LOCK_IS_HELD(old) && _DRM_LOCKING_CONTEXT(old) != context) {
DRM_ERROR("%d freed heavyweight lock held by %d\n",
context, _DRM_LOCKING_CONTEXT(old));
return 1;
}
- wake_up_interruptible(&dev->lock.lock_queue);
+ wake_up_interruptible(&lock_data->lock_queue);
return 0;
}
} while (prev != old);
return 0;
}
+
+/**
+ * This function returns immediately and takes the hw lock
+ * with the kernel context if it is free, otherwise it gets the highest priority when and if
+ * it is eventually released.
+ *
+ * This guarantees that the kernel will _eventually_ have the lock _unless_ it is held
+ * by a blocked process. (In the latter case an explicit wait for the hardware lock would cause
+ * a deadlock, which is why the "idlelock" was invented).
+ *
+ * This should be sufficient to wait for GPU idle without
+ * having to worry about starvation.
+ */
+
+void drm_idlelock_take(drm_lock_data_t *lock_data)
+{
+ int ret = 0;
+
+ spin_lock(&lock_data->spinlock);
+ lock_data->kernel_waiters++;
+ if (!lock_data->idle_has_lock) {
+
+ spin_unlock(&lock_data->spinlock);
+ ret = drm_lock_take(lock_data, DRM_KERNEL_CONTEXT);
+ spin_lock(&lock_data->spinlock);
+
+ if (ret == 1)
+ lock_data->idle_has_lock = 1;
+ }
+ spin_unlock(&lock_data->spinlock);
+}
+EXPORT_SYMBOL(drm_idlelock_take);
+
+void drm_idlelock_release(drm_lock_data_t *lock_data)
+{
+ unsigned int old, prev;
+ volatile unsigned int *lock = &lock_data->hw_lock->lock;
+
+ spin_lock(&lock_data->spinlock);
+ if (--lock_data->kernel_waiters == 0) {
+ if (lock_data->idle_has_lock) {
+ do {
+ old = *lock;
+ prev = cmpxchg(lock, old, DRM_KERNEL_CONTEXT);
+ } while (prev != old);
+ wake_up_interruptible(&lock_data->lock_queue);
+ lock_data->idle_has_lock = 0;
+ }
+ }
+ spin_unlock(&lock_data->spinlock);
+}
+EXPORT_SYMBOL(drm_idlelock_release);
+
+
+int drm_i_have_hw_lock(struct file *filp)
+{
+ DRM_DEVICE;
+
+ return (priv->lock_count && dev->lock.hw_lock &&
+ _DRM_LOCK_IS_HELD(dev->lock.hw_lock->lock) &&
+ dev->lock.filp == filp);
+}
+
+EXPORT_SYMBOL(drm_i_have_hw_lock);
git://bbs.cooldavid.org / net-next-2.6.git / commitdiff