On Tue, 15 Jul 2014 17:25:23 +0900 Hyogi Gim <[email protected]> wrote:
> In rtc_suspend() and rtc_resume(), the error after rtc_read_time() is not
> checked. If rtc device fail to read time, we cannot guarantee the following
> process.
>
> Add the verification code for returned rtc_read_time() error.
>
> ...
>
> --- a/drivers/rtc/class.c
> +++ b/drivers/rtc/class.c
> @@ -53,6 +53,7 @@ static int rtc_suspend(struct device *dev)
> struct rtc_device *rtc = to_rtc_device(dev);
> struct rtc_time tm;
> struct timespec delta, delta_delta;
> + int err;
>
> if (has_persistent_clock())
> return 0;
> @@ -61,7 +62,12 @@ static int rtc_suspend(struct device *dev)
> return 0;
>
> /* snapshot the current RTC and system time at suspend*/
> - rtc_read_time(rtc, &tm);
> + err = rtc_read_time(rtc, &tm);
> + if (err < 0) {
> + pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
> + return 0;
> + }
OK, it makes no sense to go ahead and set the system time from a
garbage rtc_time.
But I'm wondering if we should propagate the error back to the
rtc_suspend() caller. What does the PM core do if a particular
device's ->suspend or ->resume fails?
> getnstimeofday(&old_system);
> rtc_tm_to_time(&tm, &old_rtc.tv_sec);
>
> @@ -94,6 +100,7 @@ static int rtc_resume(struct device *dev)
> struct rtc_time tm;
> struct timespec new_system, new_rtc;
> struct timespec sleep_time;
> + int err;
>
> if (has_persistent_clock())
> return 0;
> @@ -104,7 +111,12 @@ static int rtc_resume(struct device *dev)
>
> /* snapshot the current rtc and system time at resume */
> getnstimeofday(&new_system);
> - rtc_read_time(rtc, &tm);
> + err = rtc_read_time(rtc, &tm);
> + if (err < 0) {
> + pr_debug("%s: fail to read rtc time\n", dev_name(&rtc->dev));
> + return 0;
> + }
> +
> if (rtc_valid_tm(&tm) != 0) {
> pr_debug("%s: bogus resume time\n", dev_name(&rtc->dev));
> return 0;
--
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