2019-01-31 09:38:00

by Joakim Zhang

[permalink] [raw]
Subject: [PATCH] can: flexcan: fix timeout when set small bitrate

Current we can meet timeout issue when setting a small bitrate like 10000
as follows on i.MX6UL EVK board (ipg clock = 66MHZ, per clock = 30MHZ):
root@imx6ul7d:~# ip link set can0 up type can bitrate 10000
A link change request failed with some changes committed already.
Interface can0 may have been left with an inconsistent configuration, please check.
RTNETLINK answers: Connection timed out

It is caused by calling of flexcan_chip_unfreeze() timeout.

Originally the code is using usleep_range(10, 20) for unfreeze operation,
but the patch (8badd65 can: flexcan: avoid calling usleep_range from interrupt
context) changed it into udelay(10) which is only a half delay of before,
there're also some other delay changes.

After double to FLEXCAN_TIMEOUT_US to 100 can fix the issue.

Signed-off-by: Joakim Zhang <[email protected]>
---
drivers/net/can/flexcan.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c
index 2bca867bcfaa..1f2b4db7da88 100644
--- a/drivers/net/can/flexcan.c
+++ b/drivers/net/can/flexcan.c
@@ -166,7 +166,7 @@
#define FLEXCAN_MB_CNT_LENGTH(x) (((x) & 0xf) << 16)
#define FLEXCAN_MB_CNT_TIMESTAMP(x) ((x) & 0xffff)

-#define FLEXCAN_TIMEOUT_US (50)
+#define FLEXCAN_TIMEOUT_US (100)

/* FLEXCAN hardware feature flags
*
--
2.17.1



2019-01-31 10:10:13

by Aisheng Dong

[permalink] [raw]
Subject: RE: [PATCH] can: flexcan: fix timeout when set small bitrate

> -----Original Message-----
> From: Joakim Zhang
> Sent: Thursday, January 31, 2019 5:37 PM
> To: [email protected]; [email protected]
> Cc: [email protected]; [email protected];
> [email protected]; dl-linux-imx <[email protected]>; Joakim
> Zhang <[email protected]>
> Subject: [PATCH] can: flexcan: fix timeout when set small bitrate
>
> Current we can meet timeout issue when setting a small bitrate like 10000 as
> follows on i.MX6UL EVK board (ipg clock = 66MHZ, per clock = 30MHZ):
> root@imx6ul7d:~# ip link set can0 up type can bitrate 10000 A link change
> request failed with some changes committed already.
> Interface can0 may have been left with an inconsistent configuration, please
> check.
> RTNETLINK answers: Connection timed out
>
> It is caused by calling of flexcan_chip_unfreeze() timeout.
>
> Originally the code is using usleep_range(10, 20) for unfreeze operation, but
> the patch (8badd65 can: flexcan: avoid calling usleep_range from interrupt
> context) changed it into udelay(10) which is only a half delay of before,
> there're also some other delay changes.
>
> After double to FLEXCAN_TIMEOUT_US to 100 can fix the issue.
>
> Signed-off-by: Joakim Zhang <[email protected]>

Reviewed-by: Dong Aisheng <[email protected]>

Regards
Dong Aisheng

2019-02-14 17:39:03

by Joakim Zhang

[permalink] [raw]
Subject: RE: [PATCH] can: flexcan: fix timeout when set small bitrate


Kindly Ping...

Reviewed-by: Dong Aisheng <[email protected]>

Best Regards,
Joakim Zhang

> -----Original Message-----
> From: Joakim Zhang
> Sent: 2019??1??31?? 17:37
> To: [email protected]; [email protected]
> Cc: [email protected]; [email protected];
> [email protected]; dl-linux-imx <[email protected]>; Joakim
> Zhang <[email protected]>
> Subject: [PATCH] can: flexcan: fix timeout when set small bitrate
>
> Current we can meet timeout issue when setting a small bitrate like 10000 as
> follows on i.MX6UL EVK board (ipg clock = 66MHZ, per clock = 30MHZ):
> root@imx6ul7d:~# ip link set can0 up type can bitrate 10000 A link change
> request failed with some changes committed already.
> Interface can0 may have been left with an inconsistent configuration, please
> check.
> RTNETLINK answers: Connection timed out
>
> It is caused by calling of flexcan_chip_unfreeze() timeout.
>
> Originally the code is using usleep_range(10, 20) for unfreeze operation, but
> the patch (8badd65 can: flexcan: avoid calling usleep_range from interrupt
> context) changed it into udelay(10) which is only a half delay of before,
> there're also some other delay changes.
>
> After double to FLEXCAN_TIMEOUT_US to 100 can fix the issue.
>
> Signed-off-by: Joakim Zhang <[email protected]>
> ---
> drivers/net/can/flexcan.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/can/flexcan.c b/drivers/net/can/flexcan.c index
> 2bca867bcfaa..1f2b4db7da88 100644
> --- a/drivers/net/can/flexcan.c
> +++ b/drivers/net/can/flexcan.c
> @@ -166,7 +166,7 @@
> #define FLEXCAN_MB_CNT_LENGTH(x) (((x) & 0xf) << 16)
> #define FLEXCAN_MB_CNT_TIMESTAMP(x) ((x) & 0xffff)
>
> -#define FLEXCAN_TIMEOUT_US (50)
> +#define FLEXCAN_TIMEOUT_US (100)
>
> /* FLEXCAN hardware feature flags
> *
> --
> 2.17.1

2019-02-27 11:07:28

by Marc Kleine-Budde

[permalink] [raw]
Subject: Re: [PATCH] can: flexcan: fix timeout when set small bitrate

On 1/31/19 10:37 AM, Joakim Zhang wrote:
> Current we can meet timeout issue when setting a small bitrate like 10000
> as follows on i.MX6UL EVK board (ipg clock = 66MHZ, per clock = 30MHZ):
> root@imx6ul7d:~# ip link set can0 up type can bitrate 10000
> A link change request failed with some changes committed already.
> Interface can0 may have been left with an inconsistent configuration, please check.
> RTNETLINK answers: Connection timed out
>
> It is caused by calling of flexcan_chip_unfreeze() timeout.
>
> Originally the code is using usleep_range(10, 20) for unfreeze operation,
> but the patch (8badd65 can: flexcan: avoid calling usleep_range from interrupt
> context) changed it into udelay(10) which is only a half delay of before,
> there're also some other delay changes.
>
> After double to FLEXCAN_TIMEOUT_US to 100 can fix the issue.
>
> Signed-off-by: Joakim Zhang <[email protected]>

Applied to linux-can

Tnx,
Marc

--
Pengutronix e.K. | Marc Kleine-Budde |
Industrial Linux Solutions | Phone: +49-231-2826-924 |
Vertretung West/Dortmund | Fax: +49-5121-206917-5555 |
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