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authorAlexei Lazar <alazar@nvidia.com>2025-07-23 10:44:30 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2025-08-15 12:13:47 +0200
commitc04bc84aa5e962da35233753b3ee7b4c7fae4ac4 (patch)
tree9d5cdd80556383e4fadd1da22f1c370b17a431cf
parent7c1ae471da69c09242834e956218ea6a42dd405a (diff)
net/mlx5e: Clear Read-Only port buffer size in PBMC before update
[ Upstream commit fd4b97246a23c1149479b88490946bcfbd28de63 ] When updating the PBMC register, we read its current value, modify desired fields, then write it back. The port_buffer_size field within PBMC is Read-Only (RO). If this RO field contains a non-zero value when read, attempting to write it back will cause the entire PBMC register update to fail. This commit ensures port_buffer_size is explicitly cleared to zero after reading the PBMC register but before writing back the modified value. This allows updates to other fields in the PBMC register to succeed. Fixes: 0696d60853d5 ("net/mlx5e: Receive buffer configuration") Signed-off-by: Alexei Lazar <alazar@nvidia.com> Reviewed-by: Yael Chemla <ychemla@nvidia.com> Signed-off-by: Tariq Toukan <tariqt@nvidia.com> Link: https://patch.msgid.link/1753256672-337784-2-git-send-email-tariqt@nvidia.com Signed-off-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
-rw-r--r--drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
index 8e25f4ef5ccc..5ae787656a7c 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/port_buffer.c
@@ -331,6 +331,9 @@ static int port_set_buffer(struct mlx5e_priv *priv,
if (err)
goto out;
+ /* RO bits should be set to 0 on write */
+ MLX5_SET(pbmc_reg, in, port_buffer_size, 0);
+
err = mlx5e_port_set_pbmc(mdev, in);
out:
kfree(in);