On 5 June 2016 at 11:35, Alexander Graf <ag...@suse.de> wrote:
> While the EFI spec mandates an RTC, not every implementation actually adheres
> to that rule (or can adhere to it - some systems just don't have an RTC).
>
> For those, we really don't want to probe the EFI RTC driver at all, because if
> we do we'd get a non-functional driver that does nothing useful but only
> spills
> our kernel log with warnings.
>
> Signed-off-by: Alexander Graf <ag...@suse.de>
Acked-by: Ard Biesheuvel <ard.biesheu...@linaro.org>
> ---
> drivers/rtc/rtc-efi.c | 6 ++++++
> 1 file changed, 6 insertions(+)
>
> diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c
> index 96d3860..0130afd 100644
> --- a/drivers/rtc/rtc-efi.c
> +++ b/drivers/rtc/rtc-efi.c
> @@ -259,6 +259,12 @@ static const struct rtc_class_ops efi_rtc_ops = {
> static int __init efi_rtc_probe(struct platform_device *dev)
> {
> struct rtc_device *rtc;
> + efi_time_t eft;
> + efi_time_cap_t cap;
> +
> + /* First check if the RTC is usable */
> + if (efi.get_time(&eft, &cap) != EFI_SUCCESS)
> + return -ENODEV;
>
> rtc = devm_rtc_device_register(&dev->dev, "rtc-efi", &efi_rtc_ops,
> THIS_MODULE);
> --
> 1.8.5.6
>
