diff mbox series

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

Message ID 20210621134902.83587-7-coiby.xu@gmail.com
State New
Headers show
Series Improve the qlge driver based on drivers/staging/qlge/TODO | expand

Commit Message

Coiby Xu June 21, 2021, 1:48 p.m. UTC
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(-)

Comments

Coiby Xu June 24, 2021, 11:33 a.m. UTC | #1
On Tue, Jun 22, 2021 at 04:49:51PM +0900, Benjamin Poirier wrote:
>On 2021-06-21 21:48 +0800, Coiby Xu wrote:

>> 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;

>

>Initialization is not needed given the code below, 


Thanks for the spotting this issue!

> in fact the

>declaration can be moved to the block below.


I thought I need to put the declaration in the beginning of the
function. But it seems Linux kernel coding style doesn't require it.
I'll move it to the else block below then.

>

>>  	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

>> +		 */

>

>It seems this comment is incomplete. Also, it's "flow control", not

>"follow control".


Ah, yes. I should state it as "Don't let the pause parameter be 
overwritten by be overwritten by the firmware.". And thanks for
correcting the typo.
>

>> +		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

>>


-- 
Best regards,
Coiby
diff mbox series

Patch

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;