A normal wait adds to the front of the tail. By doing something similar to fence_default_wait the fence code can run without racing.
This is a complete fix for "panic on suspend from KDE with radeon", and a partial fix for "Radeon: System pauses on TAHITI". On tahiti si_irq_set needs to be fixed too, to completely flush the writes before radeon_fence_activity is called in radeon_fence_enable_signaling. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=90741 Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=90861 Signed-off-by: Maarten Lankhorst <maarten.lankhorst at ubuntu.com> Reported-by: Jon Arne Jørgensen <jonjon.arnearne at gmail.com> Reported-and-tested-by: Gustaw Smolarczyk <wielkiegie at gmail.com> Cc: stable at vger.kernel.org (v3.18+) --- drivers/gpu/drm/radeon/radeon_fence.c | 68 +++++++++++++++++++++++------------ 1 file changed, 45 insertions(+), 23 deletions(-) diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c index d13d1b5a859f..df09ca7c4889 100644 --- a/drivers/gpu/drm/radeon/radeon_fence.c +++ b/drivers/gpu/drm/radeon/radeon_fence.c @@ -1030,37 +1030,59 @@ static inline bool radeon_test_signaled(struct radeon_fence *fence) return test_bit(FENCE_FLAG_SIGNALED_BIT, &fence->base.flags); } +struct radeon_wait_cb { + struct fence_cb base; + struct task_struct *task; +}; + +static void +radeon_fence_wait_cb(struct fence *fence, struct fence_cb *cb) +{ + struct radeon_wait_cb *wait = + container_of(cb, struct radeon_wait_cb, base); + + wake_up_process(wait->task); +} + static signed long radeon_fence_default_wait(struct fence *f, bool intr, signed long t) { struct radeon_fence *fence = to_radeon_fence(f); struct radeon_device *rdev = fence->rdev; - bool signaled; + struct radeon_wait_cb cb; - fence_enable_sw_signaling(&fence->base); + cb.task = current; - /* - * This function has to return -EDEADLK, but cannot hold - * exclusive_lock during the wait because some callers - * may already hold it. This means checking needs_reset without - * lock, and not fiddling with any gpu internals. - * - * The callback installed with fence_enable_sw_signaling will - * run before our wait_event_*timeout call, so we will see - * both the signaled fence and the changes to needs_reset. - */ + if (fence_add_callback(f, &cb.base, radeon_fence_wait_cb)) + return t; + + while (t > 0) { + if (intr) + set_current_state(TASK_INTERRUPTIBLE); + else + set_current_state(TASK_UNINTERRUPTIBLE); + + /* + * radeon_test_signaled must be called after + * set_current_state to prevent a race with wake_up_process + */ + if (radeon_test_signaled(fence)) + break; + + if (rdev->needs_reset) { + t = -EDEADLK; + break; + } + + t = schedule_timeout(t); + + if (t > 0 && intr && signal_pending(current)) + t = -ERESTARTSYS; + } + + __set_current_state(TASK_RUNNING); + fence_remove_callback(f, &cb.base); - if (intr) - t = wait_event_interruptible_timeout(rdev->fence_queue, - ((signaled = radeon_test_signaled(fence)) || - rdev->needs_reset), t); - else - t = wait_event_timeout(rdev->fence_queue, - ((signaled = radeon_test_signaled(fence)) || - rdev->needs_reset), t); - - if (t > 0 && !signaled) - return -EDEADLK; return t; } -- 2.3.0
