From d12fb13f23199faa7e536acec1db49068e5a067d Mon Sep 17 00:00:00 2001
From: shaoyunl <Shaoyun.Liu@amd.com>
Date: Wed, 1 Nov 2017 19:21:56 -0400
Subject: [PATCH] drm/amdkfd: Fix SDMA ring buffer size calculation
Git-commit: d12fb13f23199faa7e536acec1db49068e5a067d
Patch-mainline: v4.15-rc2
References: bsc#1051510
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
--- a/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c
+++ b/drivers/gpu/drm/amd/amdkfd/kfd_mqd_manager_cik.c
@@ -202,8 +202,8 @@ static int update_mqd_sdma(struct mqd_ma
struct cik_sdma_rlc_registers *m;
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;