Am 30.04.2018 um 17:38 schrieb Daniel Vetter:
On Sun, Apr 29, 2018 at 09:08:31AM +0200, Christian König wrote:
NAK, there is a subtitle but major difference:
- if (rdev->needs_reset) {
- t = -EDEADLK;
- break;
- }
Without that the whole radeon GPU reset code breaks.
Oops I've missed that. How does this work when you register a callback
using ->enable_signaling and then block on it? Everything just dies?
The short answer is we simply avoid using enable_signaling() from inside
driver IOCTLs.
We have lots of users of that for buffer/fence sharing. A really ugly, but
probably working fix for this would be a kthread worker that just looks
for ->needs_reset and force-completes all fences with
dma_fence_set_error(-EIO), which is kinda what's supposed to happen here
anyway.
That actually won't help. Radeon does this dance to return an error from
dma_fence_wait() when the GPU needs a reset.
This way all IOCTLs should return to userspace with -EAGAIN and when
they are restarted we block for the running GPU reset to finish.
I was against this approach, but it works as long as radeon only has to
deal with it's own fences.
Christian.
-Daniel
Regards,
Christian.
Am 27.04.2018 um 08:17 schrieb Daniel Vetter:
It's a copy of dma_fence_default_wait, written slightly differently.
Signed-off-by: Daniel Vetter <daniel.vetter@xxxxxxxx>
Cc: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: "Christian König" <christian.koenig@xxxxxxx>
Cc: "David (ChunMing) Zhou" <David1.Zhou@xxxxxxx>
Cc: amd-gfx@xxxxxxxxxxxxxxxxxxxxx
---
drivers/gpu/drm/radeon/radeon_fence.c | 63 ---------------------------
1 file changed, 63 deletions(-)
diff --git a/drivers/gpu/drm/radeon/radeon_fence.c b/drivers/gpu/drm/radeon/radeon_fence.c
index e86f2bd38410..32690a525bfc 100644
--- a/drivers/gpu/drm/radeon/radeon_fence.c
+++ b/drivers/gpu/drm/radeon/radeon_fence.c
@@ -1051,72 +1051,9 @@ static const char *radeon_fence_get_timeline_name(struct dma_fence *f)
}
}
-static inline bool radeon_test_signaled(struct radeon_fence *fence)
-{
- return test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &fence->base.flags);
-}
-
-struct radeon_wait_cb {
- struct dma_fence_cb base;
- struct task_struct *task;
-};
-
-static void
-radeon_fence_wait_cb(struct dma_fence *fence, struct dma_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 dma_fence *f, bool intr,
- signed long t)
-{
- struct radeon_fence *fence = to_radeon_fence(f);
- struct radeon_device *rdev = fence->rdev;
- struct radeon_wait_cb cb;
-
- cb.task = current;
-
- if (dma_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);
- dma_fence_remove_callback(f, &cb.base);
-
- return t;
-}
-
const struct dma_fence_ops radeon_fence_ops = {
.get_driver_name = radeon_fence_get_driver_name,
.get_timeline_name = radeon_fence_get_timeline_name,
.enable_signaling = radeon_fence_enable_signaling,
.signaled = radeon_fence_is_signaled,
- .wait = radeon_fence_default_wait,
- .release = NULL,
};
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