Hi,
On Mon, Dec 17, 2018 at 2:42 PM Tony Lindgren <tony@xxxxxxxxxxx> wrote:
>
> At least HiKey board can fail to bring up wireless interface again
> if the interface is brought down and up with no delay inbetween.
>
> This can be done tested with:
>
> # while true; do ifconfig wlan0 down; ifconfig wlan0 up; done
>
> According to Ricardo Salveti <rsalveti@xxxxxxxxxxxx>, we need to
> wait between 30 - 40 ms on HiKey. This seems to happen when we
> get -EBUSY returned by pm_runtime_put() basedon the check in
> rpm_check_suspend_allowed(). But as it still unclear if part of
> the delay needed is because of capacitance, let's always do a
> at least 50 ms msleep even if no -EBUSY is returned.
>
> Cc: Anders Roxell <anders.roxell@xxxxxxxxxx>
> Cc: Eyal Reizer <eyalr@xxxxxx>
> Cc: John Stultz <john.stultz@xxxxxxxxxx>
> Cc: Ricardo Salveti <rsalveti@xxxxxxxxxxxx>
> Cc: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
> Reported-by: Ricardo Salveti <rsalveti@xxxxxxxxxxxx>
> Fixes: 60f36637bbbd ("wlcore: sdio: allow pm to handle sdio power")
> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>
> ---
>
> Uffe, do you have some better ideas on how to fix this issue?
>
> ---
> drivers/net/wireless/ti/wlcore/sdio.c | 13 ++++++++++++-
> 1 file changed, 12 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/ti/wlcore/sdio.c b/drivers/net/wireless/ti/wlcore/sdio.c
> --- a/drivers/net/wireless/ti/wlcore/sdio.c
> +++ b/drivers/net/wireless/ti/wlcore/sdio.c
> @@ -174,7 +174,7 @@ static int wl12xx_sdio_power_off(struct wl12xx_sdio_glue *glue)
> {
> struct sdio_func *func = dev_to_sdio_func(glue->dev);
> struct mmc_card *card = func->card;
> - int error;
> + int error, retries = 5;
>
> sdio_claim_host(func);
> sdio_disable_func(func);
> @@ -188,6 +188,17 @@ static int wl12xx_sdio_power_off(struct wl12xx_sdio_glue *glue)
> return error;
> }
>
> + /* Wait a bit to ensure the card gets power off. Otherwise
> + * bringing interface down and up again may not power off the
> + * card inbetween. And then firmware load will fail on trying
> + * to bring the card up again. We need to wait between 30 - 40
> + * ms for this based on measurements on HiKey board.
> + */
> + do {
> + msleep(50);
> + } while (error == -EBUSY && !pm_runtime_suspended(&card->dev) &&
> + retries--);
> +
> return 0;
> }
>
> --
> 2.19.2
Tested with 'while true; do ifconfig wlan0 down; ifconfig wlan0 up;
done' for 3 hours on HiKey, HiKey960 and BeagleBone Black Wireless, no
issues.
Tested-by: Ricardo Salveti <rsalveti@xxxxxxxxxxxx>
Thanks,
--
Ricardo Salveti de Araujo
