This is a note to let you know that I've just added the patch titled

drm/amdkfd: Fix SDMA ring buffer size calculation

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: drm-amdkfd-fix-sdma-ring-buffer-size-calculation.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From foo@baz Thu Feb 1 13:45:42 CET 2018

From: shaoyunl Shaoyun.Liu@amd.com Date: Wed, 1 Nov 2017 19:21:56 -0400 Subject: drm/amdkfd: Fix SDMA ring buffer size calculation

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@verizon.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- 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 @@ -205,8 +205,8 @@ 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;

Patches currently in stable-queue which might be from Shaoyun.Liu@amd.com are

queue-4.14/drm-amdkfd-fix-sdma-ring-buffer-size-calculation.patch