From: Jay Cornwall <jay.cornw...@amd.com>
Gfx8 HW incorrectly clamps CP_HQD_EOP_CONTROL.EOP_SIZE, which can
lead to scheduling deadlock due to SE EOP done counter overflow.
Enforce a EOP queue size limit which prevents the CP from sending
more than 0xFF events at a time.
Signed-off-by: Jay Cornwall <jay.cornw...@amd.com>
Reviewed-by: Felix Kuehling <felix.kuehl...@amd.com>
Acked-by: Oded Gabbay <oded.gab...@gmail.com>
---
drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_vi.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_vi.c
b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_vi.c
index f4c8c23..98a930e 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_vi.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_vi.c
@@ -135,8 +135,15 @@ static int __update_mqd(struct mqd_manager *mm, void *mqd,
3 << CP_HQD_IB_CONTROL__MIN_IB_AVAIL_SIZE__SHIFT |
mtype << CP_HQD_IB_CONTROL__MTYPE__SHIFT;
- m->cp_hqd_eop_control |=
- ffs(q->eop_ring_buffer_size / sizeof(unsigned int)) - 1 - 1;
+ /*
+ * HW does not clamp this field correctly. Maximum EOP queue size
+ * is constrained by per-SE EOP done signal count, which is 8-bit.
+ * Limit is 0xFF EOP entries (= 0x7F8 dwords). CP will not submit
+ * more than (EOP entry count - 1) so a queue size of 0x800 dwords
+ * is safe, giving a maximum field value of 0xA.
+ */
+ m->cp_hqd_eop_control |= min(0xA,
+ ffs(q->eop_ring_buffer_size / sizeof(unsigned int)) - 1 - 1);
m->cp_hqd_eop_base_addr_lo =
lower_32_bits(q->eop_ring_buffer_address >> 8);
m->cp_hqd_eop_base_addr_hi =
--
2.7.4
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