Re: [PATCH 14/15] drm/radeon: record what is next valid wptr for each ring v2

Christian König <deathsimple@xxxxxxxxxxx> · Wed, 11 Jul 2012 10:08:24 +0200

On 10.07.2012 18:56, Jerome Glisse wrote:
On Tue, Jul 10, 2012 at 8:51 AM, Christian König
<deathsimple@xxxxxxxxxxx> wrote:
Before emitting any indirect buffer, emit the offset of the next
valid ring content if any. This allow code that want to resume
ring to resume ring right after ib that caused GPU lockup.

v2: use scratch registers instead of storing it into memory

Why using scratch register ? To minimize bus activities ?
No, but that also seems like a valid argument. If we want to reduce bus 
activity we should also disable writeback for the scratch registers .

My main intention was that a register write seems to be more failsafe 
than a memory write. For a memory write there are just more things that 
can go terribly wrong, just think of old AGP cards. Also not all rings 
can write to memory, but it seems like that everybody can do a simple 
register write.

Reading that register once in case of a lockup isn't such a big overhead 
compared what needs to be done for a complete reset.

Signed-off-by: Jerome Glisse <jglisse@xxxxxxxxxx>
Signed-off-by: Christian König <deathsimple@xxxxxxxxxxx>
---
  drivers/gpu/drm/radeon/evergreen.c   |    8 +++++++-
  drivers/gpu/drm/radeon/ni.c          |   11 ++++++++++-
  drivers/gpu/drm/radeon/r600.c        |   18 ++++++++++++++++--
  drivers/gpu/drm/radeon/radeon.h      |    1 +
  drivers/gpu/drm/radeon/radeon_ring.c |    4 ++++
  drivers/gpu/drm/radeon/rv770.c       |    4 +++-
  drivers/gpu/drm/radeon/si.c          |   22 +++++++++++++++++++---
  7 files changed, 60 insertions(+), 8 deletions(-)

diff --git a/drivers/gpu/drm/radeon/evergreen.c b/drivers/gpu/drm/radeon/evergreen.c
index f39b900..40de347 100644
--- a/drivers/gpu/drm/radeon/evergreen.c
+++ b/drivers/gpu/drm/radeon/evergreen.c
@@ -1368,7 +1368,13 @@ void evergreen_ring_ib_execute(struct radeon_device *rdev, struct radeon_ib *ib)
         /* set to DX10/11 mode */
         radeon_ring_write(ring, PACKET3(PACKET3_MODE_CONTROL, 0));
         radeon_ring_write(ring, 1);
-       /* FIXME: implement */
+
+       if (ring->rptr_save_reg) {
+               uint32_t next_rptr = ring->wptr + 2 + 4;
+               radeon_ring_write(ring, PACKET0(ring->rptr_save_reg, 0));
+               radeon_ring_write(ring, next_rptr);
+       }
+
         radeon_ring_write(ring, PACKET3(PACKET3_INDIRECT_BUFFER, 2));
         radeon_ring_write(ring,
  #ifdef __BIG_ENDIAN
diff --git a/drivers/gpu/drm/radeon/ni.c b/drivers/gpu/drm/radeon/ni.c
index f2afefb..6e3d448 100644
--- a/drivers/gpu/drm/radeon/ni.c
+++ b/drivers/gpu/drm/radeon/ni.c
@@ -855,6 +855,13 @@ void cayman_ring_ib_execute(struct radeon_device *rdev, struct radeon_ib *ib)
         /* set to DX10/11 mode */
         radeon_ring_write(ring, PACKET3(PACKET3_MODE_CONTROL, 0));
         radeon_ring_write(ring, 1);
+
+       if (ring->rptr_save_reg) {
+               uint32_t next_rptr = ring->wptr + 2 + 4;
I would rather also skip the surface sync so add another + 8
Akk, going to change that.

+               radeon_ring_write(ring, PACKET0(ring->rptr_save_reg, 0));
+               radeon_ring_write(ring, next_rptr);
+       }
+
         radeon_ring_write(ring, PACKET3(PACKET3_INDIRECT_BUFFER, 2));
         radeon_ring_write(ring,
  #ifdef __BIG_ENDIAN
@@ -981,8 +988,10 @@ static int cayman_cp_start(struct radeon_device *rdev)

  static void cayman_cp_fini(struct radeon_device *rdev)
  {
+       struct radeon_ring *ring = &rdev->ring[RADEON_RING_TYPE_GFX_INDEX];
         cayman_cp_enable(rdev, false);
-       radeon_ring_fini(rdev, &rdev->ring[RADEON_RING_TYPE_GFX_INDEX]);
+       radeon_ring_fini(rdev, ring);
+       radeon_scratch_free(rdev, ring->rptr_save_reg);
  }

  int cayman_cp_resume(struct radeon_device *rdev)
diff --git a/drivers/gpu/drm/radeon/r600.c b/drivers/gpu/drm/radeon/r600.c
index c808fa9..74fca15 100644
--- a/drivers/gpu/drm/radeon/r600.c
+++ b/drivers/gpu/drm/radeon/r600.c
@@ -2155,18 +2155,27 @@ int r600_cp_resume(struct radeon_device *rdev)
  void r600_ring_init(struct radeon_device *rdev, struct radeon_ring *ring, unsigned ring_size)
  {
         u32 rb_bufsz;
+       int r;

         /* Align ring size */
         rb_bufsz = drm_order(ring_size / 8);
         ring_size = (1 << (rb_bufsz + 1)) * 4;
         ring->ring_size = ring_size;
         ring->align_mask = 16 - 1;
+
+       r = radeon_scratch_get(rdev, &ring->rptr_save_reg);
+       if (r) {
+               DRM_ERROR("failed to get scratch reg for rptr save (%d).\n", r);
+               ring->rptr_save_reg = 0;
+       }
  }

  void r600_cp_fini(struct radeon_device *rdev)
  {
+       struct radeon_ring *ring = &rdev->ring[RADEON_RING_TYPE_GFX_INDEX];
         r600_cp_stop(rdev);
-       radeon_ring_fini(rdev, &rdev->ring[RADEON_RING_TYPE_GFX_INDEX]);
+       radeon_ring_fini(rdev, ring);
+       radeon_scratch_free(rdev, ring->rptr_save_reg);
  }


@@ -2568,7 +2577,12 @@ void r600_ring_ib_execute(struct radeon_device *rdev, struct radeon_ib *ib)
  {
         struct radeon_ring *ring = &rdev->ring[ib->ring];

-       /* FIXME: implement */
+       if (ring->rptr_save_reg) {
+               uint32_t next_rptr = ring->wptr + 2 + 4;
+               radeon_ring_write(ring, PACKET0(ring->rptr_save_reg, 0));
+               radeon_ring_write(ring, next_rptr);
+       }
+
         radeon_ring_write(ring, PACKET3(PACKET3_INDIRECT_BUFFER, 2));
         radeon_ring_write(ring,
  #ifdef __BIG_ENDIAN
diff --git a/drivers/gpu/drm/radeon/radeon.h b/drivers/gpu/drm/radeon/radeon.h
index 872270c..64d39ad 100644
--- a/drivers/gpu/drm/radeon/radeon.h
+++ b/drivers/gpu/drm/radeon/radeon.h
@@ -622,6 +622,7 @@ struct radeon_ring {
         unsigned                rptr;
         unsigned                rptr_offs;
         unsigned                rptr_reg;
+       unsigned                rptr_save_reg;
         unsigned                wptr;
         unsigned                wptr_old;
         unsigned                wptr_reg;
diff --git a/drivers/gpu/drm/radeon/radeon_ring.c b/drivers/gpu/drm/radeon/radeon_ring.c
index 0873834..ce8eb9d 100644
--- a/drivers/gpu/drm/radeon/radeon_ring.c
+++ b/drivers/gpu/drm/radeon/radeon_ring.c
@@ -451,6 +451,10 @@ static int radeon_debugfs_ring_info(struct seq_file *m, void *data)
         count = (ring->ring_size / 4) - ring->ring_free_dw;
         seq_printf(m, "wptr(0x%04x): 0x%08x\n", ring->wptr_reg, RREG32(ring->wptr_reg));
         seq_printf(m, "rptr(0x%04x): 0x%08x\n", ring->rptr_reg, RREG32(ring->rptr_reg));
+       if (ring->rptr_save_reg) {
+               seq_printf(m, "rptr next(0x%04x): 0x%08x\n", ring->rptr_save_reg,
+                          RREG32(ring->rptr_save_reg));
+       }
         seq_printf(m, "driver's copy of the wptr: 0x%08x\n", ring->wptr);
         seq_printf(m, "driver's copy of the rptr: 0x%08x\n", ring->rptr);
         seq_printf(m, "%u free dwords in ring\n", ring->ring_free_dw);
diff --git a/drivers/gpu/drm/radeon/rv770.c b/drivers/gpu/drm/radeon/rv770.c
index b4b1256..eb4704e 100644
--- a/drivers/gpu/drm/radeon/rv770.c
+++ b/drivers/gpu/drm/radeon/rv770.c
@@ -358,8 +358,10 @@ static int rv770_cp_load_microcode(struct radeon_device *rdev)

  void r700_cp_fini(struct radeon_device *rdev)
  {
+       struct radeon_ring *ring = &rdev->ring[RADEON_RING_TYPE_GFX_INDEX];
         r700_cp_stop(rdev);
-       radeon_ring_fini(rdev, &rdev->ring[RADEON_RING_TYPE_GFX_INDEX]);
+       radeon_ring_fini(rdev, ring);
+       radeon_scratch_free(rdev, ring->rptr_save_reg);
  }

  /*
diff --git a/drivers/gpu/drm/radeon/si.c b/drivers/gpu/drm/radeon/si.c
index f61b550..c7ace21 100644
--- a/drivers/gpu/drm/radeon/si.c
+++ b/drivers/gpu/drm/radeon/si.c
@@ -1765,6 +1765,12 @@ void si_ring_ib_execute(struct radeon_device *rdev, struct radeon_ib *ib)
         struct radeon_ring *ring = &rdev->ring[ib->ring];
         u32 header;

+       if (ring->rptr_save_reg) {
+               uint32_t next_rptr = ring->wptr + 2 + 4;
Same as ni I would rather also skip the surface sync so add another + 8
Dito.

+               radeon_ring_write(ring, PACKET0(ring->rptr_save_reg, 0));
+               radeon_ring_write(ring, next_rptr);
+       }
+
         if (ib->is_const_ib)
                 header = PACKET3(PACKET3_INDIRECT_BUFFER_CONST, 2);
         else
@@ -1917,10 +1923,20 @@ static int si_cp_start(struct radeon_device *rdev)

  static void si_cp_fini(struct radeon_device *rdev)
  {
+       struct radeon_ring *ring;
         si_cp_enable(rdev, false);
-       radeon_ring_fini(rdev, &rdev->ring[RADEON_RING_TYPE_GFX_INDEX]);
-       radeon_ring_fini(rdev, &rdev->ring[CAYMAN_RING_TYPE_CP1_INDEX]);
-       radeon_ring_fini(rdev, &rdev->ring[CAYMAN_RING_TYPE_CP2_INDEX]);
+
+       ring = &rdev->ring[RADEON_RING_TYPE_GFX_INDEX];
+       radeon_ring_fini(rdev, ring);
+       radeon_scratch_free(rdev, ring->rptr_save_reg);
+
+       ring = &rdev->ring[CAYMAN_RING_TYPE_CP1_INDEX];
+       radeon_ring_fini(rdev, ring);
+       radeon_scratch_free(rdev, ring->rptr_save_reg);
+
+       ring = &rdev->ring[CAYMAN_RING_TYPE_CP2_INDEX];
+       radeon_ring_fini(rdev, ring);
+       radeon_scratch_free(rdev, ring->rptr_save_reg);
  }

  static int si_cp_resume(struct radeon_device *rdev)
--
1.7.9.5

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Christian.
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