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;a=summary 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@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Feb 1 13:45:42 CET 2018 From: shaoyunl <Shaoyun.Liu@xxxxxxx> Date: Wed, 1 Nov 2017 19:21:56 -0400 Subject: drm/amdkfd: Fix SDMA ring buffer size calculation From: shaoyunl <Shaoyun.Liu@xxxxxxx> [ 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@xxxxxxx> Signed-off-by: Felix Kuehling <Felix.Kuehling@xxxxxxx> Reviewed-by: Oded Gabbay <oded.gabbay@xxxxxxxxx> Signed-off-by: Oded Gabbay <oded.gabbay@xxxxxxxxx> Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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@xxxxxxx are queue-4.14/drm-amdkfd-fix-sdma-ring-buffer-size-calculation.patch