[RFC 06/19] staging: qlge: disable flow control by default

Coiby Xu
2021-06-21T13:50:14Z

According to the TODO item,
> * the flow control implementation in firmware is buggy (sends a flood of pause
> frames, resets the link, device and driver buffer queues become
> desynchronized), disable it by default

Currently, qlge_mpi_port_cfg_work calls qlge_mb_get_port_cfg which gets
the link config from the firmware and saves it to qdev->link_config. By
default, flow control is enabled. This commit writes the
save the pause parameter of qdev->link_config and don't let it
overwritten by link settings of current port. Since qdev->link_config=0
when qdev is initialized, this could disable flow control by default and
the pause parameter value could also survive MPI resetting,
$ ethtool -a enp94s0f0
Pause parameters for enp94s0f0:
Autonegotiate: off
RX: off
TX: off

The follow control can be enabled manually,

$ ethtool -A enp94s0f0 rx on tx on
$ ethtool -a enp94s0f0
Pause parameters for enp94s0f0:
Autonegotiate: off
RX: on
TX: on

Signed-off-by: Coiby Xu <coiby.xu@gmail.com>
---
drivers/staging/qlge/TODO | 3 ---
drivers/staging/qlge/qlge_mpi.c | 11 ++++++++++-
2 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/drivers/staging/qlge/TODO b/drivers/staging/qlge/TODO
index b7a60425fcd2..8c84160b5993 100644
--- a/drivers/staging/qlge/TODO
+++ b/drivers/staging/qlge/TODO
@@ -4,9 +4,6 @@
ql_build_rx_skb(). That function is now used exclusively to handle packets
that underwent header splitting but it still contains code to handle non
split cases.
-* the flow control implementation in firmware is buggy (sends a flood of pause
- frames, resets the link, device and driver buffer queues become
- desynchronized), disable it by default
* some structures are initialized redundantly (ex. memset 0 after
alloc_etherdev())
* the driver has a habit of using runtime checks where compile time checks are
diff --git a/drivers/staging/qlge/qlge_mpi.c b/drivers/staging/qlge/qlge_mpi.c
index 2630ebf50341..0f1c7da80413 100644
--- a/drivers/staging/qlge/qlge_mpi.c
+++ b/drivers/staging/qlge/qlge_mpi.c
@@ -806,6 +806,7 @@ int qlge_mb_get_port_cfg(struct qlge_adapter *qdev)
{
struct mbox_params mbc;
struct mbox_params *mbcp = &mbc;
+ u32 saved_pause_link_config = 0;
int status = 0;

memset(mbcp, 0, sizeof(struct mbox_params));
@@ -826,7 +827,15 @@ int qlge_mb_get_port_cfg(struct qlge_adapter *qdev)
} else {
netif_printk(qdev, drv, KERN_DEBUG, qdev->ndev,
"Passed Get Port Configuration.\n");
- qdev->link_config = mbcp->mbox_out[1];
+ /*
+ * Don't let the pause parameter be overwritten by
+ *
+ * In this way, follow control can be disabled by default
+ * and the setting could also survive the MPI reset
+ */
+ saved_pause_link_config = qdev->link_config & CFG_PAUSE_STD;
+ qdev->link_config = ~CFG_PAUSE_STD & mbcp->mbox_out[1];
+ qdev->link_config |= saved_pause_link_config;
qdev->max_frame_size = mbcp->mbox_out[2];
}
return status;
--
2.32.0