Message-ID: <5542F5B5.9000206@163.com>
Date: Fri, 01 May 2015 11:40:37 +0800
From: Caesar Wang <sasukewxt@163.com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.6.0
MIME-Version: 1.0
To: Doug Anderson <dianders@chromium.org>, Wolfram Sang <wsa@the-dreams.de>
CC: Addy Ke <addy.ke@rock-chips.com>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>,
        Heiko Stuebner <heiko@sntech.de>, Max Schwarz <max.schwarz@online.de>,
        linux-kernel@vger.kernel.org, linux-rockchip@lists.infradead.org,
        linux-i2c@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH] i2c: rk3x: Increase wait timeout to 1 second
References: <1430430247-9632-1-git-send-email-dianders@chromium.org>
In-Reply-To: <1430430247-9632-1-git-send-email-dianders@chromium.org>
Content-Type: text/plain; charset=UTF-8; format=flowed
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Content-Length: 1617
Lines: 49


在 2015年05月01日 05:44, Doug Anderson 写道:
> While it's not sensible for an i2c command to _actually_ need more
> than 200ms to complete, let's increase the timeout anyway.  Why?  It
> turns out that if you've got a large number of printks going out to a
> serial console, interrupts on a CPU can be disabled for hundreds of
> milliseconds. That's not a great situation to be in to start with
> (maybe we should put a cap in vprintk_emit()) but it's pretty annoying
> to start seeing unexplained i2c timeouts.
>
> A normal system shouldn't see i2c timeouts anyway, so increasing the
> timeout should help people debugging without hurting other people
> excessively.
>
> Signed-off-by: Doug Anderson <dianders@chromium.org>
> ---
>   drivers/i2c/busses/i2c-rk3x.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/i2c/busses/i2c-rk3x.c b/drivers/i2c/busses/i2c-rk3x.c
> index 019d542..72e97e30 100644
> --- a/drivers/i2c/busses/i2c-rk3x.c
> +++ b/drivers/i2c/busses/i2c-rk3x.c
> @@ -72,7 +72,7 @@ enum {
>   #define REG_INT_ALL       0x7f
>   
>   /* Constants */
> -#define WAIT_TIMEOUT      200 /* ms */
> +#define WAIT_TIMEOUT      1000 /* ms */
Yeah, verified on veyron device.

Tested-by: Caesar Wang <wxt@rock-chips.com>


Thanks.

Caesar
>   #define DEFAULT_SCL_RATE  (100 * 1000) /* Hz */
>   
>   enum rk3x_i2c_state {


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/