Patch "drm/amdkfd: Fix SDMA ring buffer size calculation" has been added to the 4.4-stable tree

Patch "drm/amdkfd: Fix SDMA ring buffer size calculation" has been added to the 4.4-stable tree

[gregkh]

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 4.4-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-4.4 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 14:14:46 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@microsoft.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
@@ -215,8 +215,8 @@ static int update_mqd_sdma(struct mqd_ma
 	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;


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

queue-4.4/drm-amdkfd-fix-sdma-ring-buffer-size-calculation.patch