From 7368c69c033ff29e8e766f481748113c7adc1d1b Mon Sep 17 00:00:00 2001 From: Alexander Graf Date: Sun, 5 Jun 2016 11:35:56 +0200 Subject: [PATCH] rtc: efi: Fail probing if RTC reads don't work 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 Acked-by: Ard Biesheuvel Signed-off-by: Alexandre Belloni --- 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 96d38609d803..0130afd7fe88 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);