On 15.08.2014 23:52, Christian K?nig wrote:
>
> I think I've figured out what the cause of the remaining issues is while
> working on the implicit sync stuff.
>
> The issue happens when the flush is done because of a CS to the DMA ring
> and a CS to the GFX ring directly after that which depends on the DMA
> submission to be finished.
>
> In this situation we insert semaphore command so that the GFX ring wait
> for the DMA ring to finish execution and normally don't flush on the GFX
> ring a second time (the flush should be done on the DMA ring and we
> waited for that to finish).
>
> The problem here is that semaphores can't be executed on the PFP, so the
> PFP doesn't wait for the semaphore to be completed and happily starts
> fetching commands while the flush on the DMA ring isn't completed.
>
> @Michel: can you give this branch a try and see if it now works for you:
> http://cgit.freedesktop.org/~deathsimple/linux/log/?h=vm-flushing
Unfortunately not; in fact, it seems to make the problem occur even faster,
after just hundreds of piglit tests instead of after thousands.
However, based on your description above, I came up with the patch below,
which fixes the problem for me, with or without your 'drop
RADEON_FENCE_SIGNALED_SEQ' patch.
From: =?UTF-8?q?Michel=20D=C3=A4nzer?= <michel.daen...@amd.com>
Date: Mon, 18 Aug 2014 17:29:17 +0900
Subject: [PATCH] drm/radeon: Sync ME and PFP after CP semaphore waits on >=
Cayman
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Fixes lockups due to CP read GPUVM faults when running piglit on Cape
Verde.
Signed-off-by: Michel D?nzer <michel.daenzer at amd.com>
---
If the PACKET3_PFP_SYNC_ME packet was already supported before Cayman,
it might be a good idea to do this wherever possible, to avoid any
other issues the PFP running ahead of semaphore waits might cause.
drivers/gpu/drm/radeon/cik.c | 17 +++++++++++++++++
drivers/gpu/drm/radeon/ni.c | 33 +++++++++++++++++++++++++++++++++
drivers/gpu/drm/radeon/nid.h | 2 ++
drivers/gpu/drm/radeon/radeon_asic.c | 4 ++--
drivers/gpu/drm/radeon/radeon_asic.h | 4 ++++
5 files changed, 58 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/radeon/cik.c b/drivers/gpu/drm/radeon/cik.c
index 81d07e6..49707ac 100644
--- a/drivers/gpu/drm/radeon/cik.c
+++ b/drivers/gpu/drm/radeon/cik.c
@@ -3920,6 +3920,17 @@ void cik_fence_compute_ring_emit(struct radeon_device
*rdev,
radeon_ring_write(ring, 0);
}
+/**
+ * cik_semaphore_ring_emit - emit a semaphore on the CP ring
+ *
+ * @rdev: radeon_device pointer
+ * @ring: radeon ring buffer object
+ * @semaphore: radeon semaphore object
+ * @emit_wait: Is this a sempahore wait?
+ *
+ * Emits a semaphore signal/wait packet to the CP ring and prevents the PFP
+ * from running ahead of semaphore waits.
+ */
bool cik_semaphore_ring_emit(struct radeon_device *rdev,
struct radeon_ring *ring,
struct radeon_semaphore *semaphore,
@@ -3932,6 +3943,12 @@ bool cik_semaphore_ring_emit(struct radeon_device *rdev,
radeon_ring_write(ring, lower_32_bits(addr));
radeon_ring_write(ring, (upper_32_bits(addr) & 0xffff) | sel);
+ if (emit_wait) {
+ /* Prevent the PFP from running ahead of the semaphore wait */
+ radeon_ring_write(ring, PACKET3(PACKET3_PFP_SYNC_ME, 0));
+ radeon_ring_write(ring, 0x0);
+ }
+
return true;
}
diff --git a/drivers/gpu/drm/radeon/ni.c b/drivers/gpu/drm/radeon/ni.c
index ba89375..4e586c7 100644
--- a/drivers/gpu/drm/radeon/ni.c
+++ b/drivers/gpu/drm/radeon/ni.c
@@ -1363,6 +1363,39 @@ void cayman_fence_ring_emit(struct radeon_device *rdev,
radeon_ring_write(ring, 0);
}
+
+/**
+ * cayman_semaphore_ring_emit - emit a semaphore on the CP ring
+ *
+ * @rdev: radeon_device pointer
+ * @ring: radeon ring buffer object
+ * @semaphore: radeon semaphore object
+ * @emit_wait: Is this a sempahore wait?
+ *
+ * Emits a semaphore signal/wait packet to the CP ring and prevents the PFP
+ * from running ahead of semaphore waits.
+ */
+bool cayman_semaphore_ring_emit(struct radeon_device *rdev,
+ struct radeon_ring *ring,
+ struct radeon_semaphore *semaphore,
+ bool emit_wait)
+{
+ uint64_t addr = semaphore->gpu_addr;
+ unsigned sel = emit_wait ? PACKET3_SEM_SEL_WAIT :
PACKET3_SEM_SEL_SIGNAL;
+
+ radeon_ring_write(ring, PACKET3(PACKET3_MEM_SEMAPHORE, 1));
+ radeon_ring_write(ring, lower_32_bits(addr));
+ radeon_ring_write(ring, (upper_32_bits(addr) & 0xff) | sel);
+
+ if (emit_wait) {
+ /* Prevent the PFP from running ahead of the semaphore wait */
+ radeon_ring_write(ring, PACKET3(PACKET3_PFP_SYNC_ME, 0));
+ radeon_ring_write(ring, 0x0);
+ }
+
+ return true;
+}
+
void cayman_ring_ib_execute(struct radeon_device *rdev, struct radeon_ib *ib)
{
struct radeon_ring *ring = &rdev->ring[ib->ring];
diff --git a/drivers/gpu/drm/radeon/nid.h b/drivers/gpu/drm/radeon/nid.h
index 2e12e4d..dba6d37 100644
--- a/drivers/gpu/drm/radeon/nid.h
+++ b/drivers/gpu/drm/radeon/nid.h
@@ -1131,6 +1131,8 @@
#define PACKET3_DRAW_INDEX_MULTI_ELEMENT 0x36
#define PACKET3_WRITE_DATA 0x37
#define PACKET3_MEM_SEMAPHORE 0x39
+# define PACKET3_SEM_SEL_SIGNAL (0x6 << 29)
+# define PACKET3_SEM_SEL_WAIT (0x7 << 29)
#define PACKET3_MPEG_INDEX 0x3A
#define PACKET3_WAIT_REG_MEM 0x3C
#define PACKET3_MEM_WRITE 0x3D
diff --git a/drivers/gpu/drm/radeon/radeon_asic.c
b/drivers/gpu/drm/radeon/radeon_asic.c
index eeeeabe..67eb267 100644
--- a/drivers/gpu/drm/radeon/radeon_asic.c
+++ b/drivers/gpu/drm/radeon/radeon_asic.c
@@ -1555,7 +1555,7 @@ static struct radeon_asic_ring cayman_gfx_ring = {
.ib_execute = &cayman_ring_ib_execute,
.ib_parse = &evergreen_ib_parse,
.emit_fence = &cayman_fence_ring_emit,
- .emit_semaphore = &r600_semaphore_ring_emit,
+ .emit_semaphore = &cayman_semaphore_ring_emit,
.cs_parse = &evergreen_cs_parse,
.ring_test = &r600_ring_test,
.ib_test = &r600_ib_test,
@@ -1804,7 +1804,7 @@ static struct radeon_asic_ring si_gfx_ring = {
.ib_execute = &si_ring_ib_execute,
.ib_parse = &si_ib_parse,
.emit_fence = &si_fence_ring_emit,
- .emit_semaphore = &r600_semaphore_ring_emit,
+ .emit_semaphore = &cayman_semaphore_ring_emit,
.cs_parse = NULL,
.ring_test = &r600_ring_test,
.ib_test = &r600_ib_test,
diff --git a/drivers/gpu/drm/radeon/radeon_asic.h
b/drivers/gpu/drm/radeon/radeon_asic.h
index 275a5dc..6b4c757 100644
--- a/drivers/gpu/drm/radeon/radeon_asic.h
+++ b/drivers/gpu/drm/radeon/radeon_asic.h
@@ -590,6 +590,10 @@ int sumo_dpm_force_performance_level(struct radeon_device
*rdev,
*/
void cayman_fence_ring_emit(struct radeon_device *rdev,
struct radeon_fence *fence);
+bool cayman_semaphore_ring_emit(struct radeon_device *rdev,
+ struct radeon_ring *cp,
+ struct radeon_semaphore *semaphore,
+ bool emit_wait);
void cayman_pcie_gart_tlb_flush(struct radeon_device *rdev);
int cayman_init(struct radeon_device *rdev);
void cayman_fini(struct radeon_device *rdev);
--
2.1.0
--
Earthling Michel D?nzer | http://www.amd.com
Libre software enthusiast | Mesa and X developer
