Ok, that one was easy to fix. Please apply the attached patch as well.
Going to send out both for inclusion in 3.12 in a minute.
Christian.
Am 13.10.2013 22:16, schrieb Marek Olšák:
This seems to be better. It can do about 3-5 resets correctly, then
the GPU resuming fails:
[ 246.882780] [drm:cik_resume] *ERROR* cik startup failed on resume
and then the GPU is being reset again and again endlessly without success.
The dmesg of the endless resets is attached.
Marek
On Sun, Oct 13, 2013 at 2:47 PM, Christian König
<deathsimple@xxxxxxxxxxx> wrote:
I've figured out what was wrong with the patch. We need to reset the
"needs_reset" flag earlier, otherwise the IB test might think we are in a
lockup and aborts the reset after waiting for the minimum timeout period.
Please try the attached patch instead.
Thanks,
Christian.
Am 09.10.2013 14:04, schrieb Marek Olšák:
The ring test of the first compute ring always fails and it shouldn't
affect the GPU reset in any way.
I can't tell if the deadlock issue is fixed, because the GPU reset
usually fails with your patch. It always succeeded without your patch.
Marek
On Wed, Oct 9, 2013 at 1:09 PM, Christian König <deathsimple@xxxxxxxxxxx>
wrote:
Mhm, that doesn't looks like anything related but more like the reset of
the
compute ring didn't worked.
How often does that happen? And do you still get the problem where X
waits
for a fence that never comes back?
Christian.
Am 09.10.2013 12:36, schrieb Marek Olšák:
I'm afraid your patch sometimes causes the GPU reset to fail, which
had never happened before IIRC.
The dmesg log from the failure is attached.
Marek
On Tue, Oct 8, 2013 at 6:21 PM, Christian König
<deathsimple@xxxxxxxxxxx>
wrote:
Hi Marek,
please try the attached patch as a replacement for your signaling all
fences
patch. I'm not 100% sure if it fixes all issues, but it's at least a
start.
Thanks,
Christian.
Am 07.10.2013 13:08, schrieb Christian König:
First of all, I can't complain about the reliability of the hardware
GPU reset. It's mostly the kernel driver that happens to run into a
deadlock at the same time.
Alex and I spend quite some time on making this reliable again after
activating more rings and adding VM support. The main problem is that
I
couldn't figure out where the CPU deadlock comes from, cause I
couldn't
reliable reproduce the issue.
What is the content of /proc/<pid of X server>/task/*/stack and
sys/kernel/debug/dri/0/radeon_fence_info when the X server is stuck in
the
deadlock situation?
I'm pretty sure that we nearly always have a problem when two threads
are
waiting for fences on one of them detects that we have a lockup while
the
other one keeps holding the exclusive lock. Signaling all fences might
work
around that problem, but it probably would be better to fix the
underlying
issue.
Going to take a deeper look into it.
Christian.
Am 03.10.2013 02:45, schrieb Marek Olšák:
First of all, I can't complain about the reliability of the hardware
GPU reset. It's mostly the kernel driver that happens to run into a
deadlock at the same time.
Regarding the issue with fences, the problem is that the GPU reset
completes successfully according to dmesg, but X doesn't respond. I
can move the cursor on the screen, but I can't do anything else and
the UI is frozen. gdb says that X is stuck in GEM_WAIT_IDLE. I can
easily reproduce this, because it's the most common reason why a GPU
lockup leads to frozen X. The GPU actually recovers, but X is hung. I
can't tell whether the fences are just not signalled or whether there
is actually a real CPU deadlock I can't see.
This patch makes the problem go away and GPU resets are successful
(except for extreme cases, see below). With a small enough lockup
timeout, the lockups are just a minor annoyance and I thought I could
get through a piglit run just with a few tens or hundreds of GPU
resets...
A different type of deadlock showed up, though it needs a lot of
concurrently-running apps like piglit. What happened is that the
kernel driver was stuck/deadlocked in radeon_cs_ioctl presumably due
to a GPU hang while holding onto the exclusive lock, and another
thread wanting to do the GPU reset was unable to acquire the lock.
That said, I will use the patch locally, because it helps a lot. I
got
a few lockups while writing this email and I'm glad I didn't have to
reboot.
Marek
On Wed, Oct 2, 2013 at 4:50 PM, Christian König
<deathsimple@xxxxxxxxxxx>
wrote:
Possible, but I would rather guess that this doesn't work because
the
IB
test runs into a deadlock situation and so the GPU reset never fully
completes.
Can you reproduce the problem?
If you want to make GPU resets more reliable I would rather suggest
to
remove the ring lock dependency.
Then we should try to give all the fence wait functions a (reliable)
timeout and move reset handling a layer up into the ioctl functions.
But for
this you need to rip out the old PM code first.
Christian.
Marek Olšák <maraeo@xxxxxxxxx> schrieb:
I'm afraid signalling the fences with an IB test is not reliable.
Marek
On Wed, Oct 2, 2013 at 3:52 PM, Christian König
<deathsimple@xxxxxxxxxxx> wrote:
NAK, after recovering from a lockup the first thing we do is
signalling all remaining fences with an IB test.
If we don't recover we indeed signal all fences manually.
Signalling all fences regardless of the outcome of the reset
creates
problems with both types of partial resets.
Christian.
Marek Olšák <maraeo@xxxxxxxxx> schrieb:
From: Marek Olšák <marek.olsak@xxxxxxx>
After a lockup, fences are not signalled sometimes, causing
the GEM_WAIT_IDLE ioctl to never return, which sometimes results
in an X server freeze.
This fixes only one of many deadlocks which can occur during a
lockup.
Signed-off-by: Marek Olšák <marek.olsak@xxxxxxx>
---
drivers/gpu/drm/radeon/radeon_device.c | 5 +++++
1 file changed, 5 insertions(+)
diff --git a/drivers/gpu/drm/radeon/radeon_device.c
b/drivers/gpu/drm/radeon/radeon_device.c
index 841d0e0..7b97baa 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1552,6 +1552,11 @@ int radeon_gpu_reset(struct radeon_device
*rdev)
radeon_save_bios_scratch_regs(rdev);
/* block TTM */
resched =
ttm_bo_lock_delayed_workqueue(&rdev->mman.bdev);
+
+ mutex_lock(&rdev->ring_lock);
+ radeon_fence_driver_force_completion(rdev);
+ mutex_unlock(&rdev->ring_lock);
+
radeon_pm_suspend(rdev);
radeon_suspend(rdev);
--
1.8.1.2
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>From 3b690a7b016dc63ef49ae7ac593c8f7f09f80d0d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@xxxxxxx>
Date: Mon, 14 Oct 2013 11:11:28 +0200
Subject: [PATCH 1/2] drm/radeon: stop the leaks in cik_ib_test
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Stop leaking IB memory and scratch register space when the test fails.
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
---
drivers/gpu/drm/radeon/cik.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
index b874ccd..8f393df 100644
--- a/drivers/gpu/drm/radeon/cik.c
+++ b/drivers/gpu/drm/radeon/cik.c
@@ -3182,6 +3182,7 @@ int cik_ib_test(struct radeon_device *rdev, struct radeon_ring *ring)
r = radeon_ib_get(rdev, ring->idx, &ib, NULL, 256);
if (r) {
DRM_ERROR("radeon: failed to get ib (%d).\n", r);
+ radeon_scratch_free(rdev, scratch);
return r;
}
ib.ptr[0] = PACKET3(PACKET3_SET_UCONFIG_REG, 1);
@@ -3198,6 +3199,8 @@ int cik_ib_test(struct radeon_device *rdev, struct radeon_ring *ring)
r = radeon_fence_wait(ib.fence, false);
if (r) {
DRM_ERROR("radeon: fence wait failed (%d).\n", r);
+ radeon_scratch_free(rdev, scratch);
+ radeon_ib_free(rdev, &ib);
return r;
}
for (i = 0; i < rdev->usec_timeout; i++) {
--
1.8.1.2
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