[PATCH AUTOSEL for 4.4 11/35] drm/amdkfd: Fix SDMA ring buffer size calculation

Sasha Levin
2018-01-24T04:29:47Z

From: shaoyunl <Shaoyun.Liu@amd.com>

[ Upstream commit d12fb13f23199faa7e536acec1db49068e5a067d ]

ffs function return the position of the first bit set on 1 based.
(bit zero returns 1).

Signed-off-by: shaoyun liu <shaoyun.liu@amd.com>
Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
Reviewed-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Oded Gabbay <oded.gabbay@gmail.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
---
drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c
index d83de985e88c..8577a563600f 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c
@@ -215,8 +215,8 @@ static int update_mqd_sdma(struct mqd_manager *mm, void *mqd,
BUG_ON(!mm || !mqd || !q);

m = get_sdma_mqd(mqd);
- m->sdma_rlc_rb_cntl = ffs(q->queue_size / sizeof(unsigned int)) <<
- SDMA0_RLC0_RB_CNTL__RB_SIZE__SHIFT |
+ m->sdma_rlc_rb_cntl = (ffs(q->queue_size / sizeof(unsigned int)) - 1)
+ << SDMA0_RLC0_RB_CNTL__RB_SIZE__SHIFT |
q->vmid << SDMA0_RLC0_RB_CNTL__RB_VMID__SHIFT |
1 << SDMA0_RLC0_RB_CNTL__RPTR_WRITEBACK_ENABLE__SHIFT |
6 << SDMA0_RLC0_RB_CNTL__RPTR_WRITEBACK_TIMER__SHIFT;
--
2.11.0