Re: [RFC PATCH 1/3] efi-rtc: Remove wakeup functionality

[Feng Tang <feng.tang@xxxxxxxxxxxxxxxxx>]

On Mon, Jul 14, 2025 at 08:08:45AM +0200, Ard Biesheuvel wrote:
> From: Ard Biesheuvel <ardb@xxxxxxxxxx>
> 
> The EFI rtc driver is used by non-x86 architectures only, and exposes
> the get/set wakeup time functionality provided by the underlying
> platform. This is usually broken on most platforms, and not widely used
> to begin with [if at all], so let's just remove it.

This solves the problem reported in 
https://lore.kernel.org/all/20250710084151.55003-1-feng.tang@xxxxxxxxxxxxxxxxx/T/#u

Tested-by: Feng Tang <feng.tang@xxxxxxxxxxxxxxxxx>

Thanks!

- Feng

> 
> Signed-off-by: Ard Biesheuvel <ardb@xxxxxxxxxx>
> ---
>  drivers/rtc/rtc-efi.c | 76 +-------------------
>  1 file changed, 2 insertions(+), 74 deletions(-)
> 
> diff --git a/drivers/rtc/rtc-efi.c b/drivers/rtc/rtc-efi.c
> index fa8bf82df948..b4f44999ef0f 100644
> --- a/drivers/rtc/rtc-efi.c
> +++ b/drivers/rtc/rtc-efi.c
> @@ -112,48 +112,6 @@ convert_from_efi_time(efi_time_t *eft, struct rtc_time 
> *wtime)
>       return true;
>  }
>  
> -static int efi_read_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
> -{
> -     efi_time_t eft;
> -     efi_status_t status;
> -
> -     /*
> -      * As of EFI v1.10, this call always returns an unsupported status
> -      */
> -     status = efi.get_wakeup_time((efi_bool_t *)&wkalrm->enabled,
> -                                  (efi_bool_t *)&wkalrm->pending, &eft);
> -
> -     if (status != EFI_SUCCESS)
> -             return -EINVAL;
> -
> -     if (!convert_from_efi_time(&eft, &wkalrm->time))
> -             return -EIO;
> -
> -     return rtc_valid_tm(&wkalrm->time);
> -}
> -
> -static int efi_set_alarm(struct device *dev, struct rtc_wkalrm *wkalrm)
> -{
> -     efi_time_t eft;
> -     efi_status_t status;
> -
> -     convert_to_efi_time(&wkalrm->time, &eft);
> -
> -     /*
> -      * XXX Fixme:
> -      * As of EFI 0.92 with the firmware I have on my
> -      * machine this call does not seem to work quite
> -      * right
> -      *
> -      * As of v1.10, this call always returns an unsupported status
> -      */
> -     status = efi.set_wakeup_time((efi_bool_t)wkalrm->enabled, &eft);
> -
> -     dev_warn(dev, "write status is %d\n", (int)status);
> -
> -     return status == EFI_SUCCESS ? 0 : -EINVAL;
> -}
> -
>  static int efi_read_time(struct device *dev, struct rtc_time *tm)
>  {
>       efi_status_t status;
> @@ -188,17 +146,13 @@ static int efi_set_time(struct device *dev, struct 
> rtc_time *tm)
>  
>  static int efi_procfs(struct device *dev, struct seq_file *seq)
>  {
> -     efi_time_t        eft, alm;
> +     efi_time_t        eft;
>       efi_time_cap_t    cap;
> -     efi_bool_t        enabled, pending;
> -     struct rtc_device *rtc = dev_get_drvdata(dev);
>  
>       memset(&eft, 0, sizeof(eft));
> -     memset(&alm, 0, sizeof(alm));
>       memset(&cap, 0, sizeof(cap));
>  
>       efi.get_time(&eft, &cap);
> -     efi.get_wakeup_time(&enabled, &pending, &alm);
>  
>       seq_printf(seq,
>                  "Time\t\t: %u:%u:%u.%09u\n"
> @@ -214,26 +168,6 @@ static int efi_procfs(struct device *dev, struct 
> seq_file *seq)
>               /* XXX fixme: convert to string? */
>               seq_printf(seq, "Timezone\t: %u\n", eft.timezone);
>  
> -     if (test_bit(RTC_FEATURE_ALARM, rtc->features)) {
> -             seq_printf(seq,
> -                        "Alarm Time\t: %u:%u:%u.%09u\n"
> -                        "Alarm Date\t: %u-%u-%u\n"
> -                        "Alarm Daylight\t: %u\n"
> -                        "Enabled\t\t: %s\n"
> -                        "Pending\t\t: %s\n",
> -                        alm.hour, alm.minute, alm.second, alm.nanosecond,
> -                        alm.year, alm.month, alm.day,
> -                        alm.daylight,
> -                        enabled == 1 ? "yes" : "no",
> -                        pending == 1 ? "yes" : "no");
> -
> -             if (alm.timezone == EFI_UNSPECIFIED_TIMEZONE)
> -                     seq_puts(seq, "Timezone\t: unspecified\n");
> -             else
> -                     /* XXX fixme: convert to string? */
> -                     seq_printf(seq, "Timezone\t: %u\n", alm.timezone);
> -     }
> -
>       /*
>        * now prints the capabilities
>        */
> @@ -249,8 +183,6 @@ static int efi_procfs(struct device *dev, struct seq_file 
> *seq)
>  static const struct rtc_class_ops efi_rtc_ops = {
>       .read_time      = efi_read_time,
>       .set_time       = efi_set_time,
> -     .read_alarm     = efi_read_alarm,
> -     .set_alarm      = efi_set_alarm,
>       .proc           = efi_procfs,
>  };
>  
> @@ -271,11 +203,7 @@ static int __init efi_rtc_probe(struct platform_device 
> *dev)
>       platform_set_drvdata(dev, rtc);
>  
>       rtc->ops = &efi_rtc_ops;
> -     clear_bit(RTC_FEATURE_UPDATE_INTERRUPT, rtc->features);
> -     if (efi_rt_services_supported(EFI_RT_SUPPORTED_WAKEUP_SERVICES))
> -             set_bit(RTC_FEATURE_ALARM_WAKEUP_ONLY, rtc->features);
> -     else
> -             clear_bit(RTC_FEATURE_ALARM, rtc->features);
> +     clear_bit(RTC_FEATURE_ALARM, rtc->features);
>  
>       device_init_wakeup(&dev->dev, true);
>  
> -- 
> 2.50.0.727.gbf7dc18ff4-goog