From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ard Biesheuvel Subject: [PATCH 06/14] efi/reboot: Fall back to original power-off method if EFI_RESET_SHUTDOWN returns Date: Fri, 18 Aug 2017 20:49:39 +0100 Message-ID: <20170818194947.19347-7-ard.biesheuvel@linaro.org> References: <20170818194947.19347-1-ard.biesheuvel@linaro.org> Return-path: In-Reply-To: <20170818194947.19347-1-ard.biesheuvel-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org> Sender: linux-efi-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: linux-efi-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Ingo Molnar , Thomas Gleixner , "H . Peter Anvin" Cc: Hans de Goede , Ard Biesheuvel , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Mark Salter , Len Brown , "Rafael J. Wysocki" , Andy Shevchenko , Peter Jones , Matt Fleming List-Id: linux-efi@vger.kernel.org From: Hans de Goede Commit 44be28e9dd98 ("x86/reboot: Add EFI reboot quirk for ACPI Hardware Reduced flag") sets pm_power_off to efi_power_off() when the acpi_gbl_reduced_hardware flag is set. According to its commit message this is necessary because: "BayTrail-T class of hardware requires EFI in order to powerdown and reboot and no other reliable method exists" But I have a Bay Trail CR tablet where the EFI_RESET_SHUTDOWN call does not work, it simply returns without doing anything (AFAICT). So it seems that some Bay Trail devices must use EFI for power-off, while for others only ACPI works. Note that efi_power_off() only gets used if the platform code defines efi_poweroff_required() and that returns true, this currently only ever happens on x86. Since on the devices which need ACPI for power-off the EFI_RESET_SHUTDOWN call simply returns, this patch makes the efi-reboot code remember the old pm_power_off handler and if EFI_RESET_SHUTDOWN returns it falls back to calling that. This seems preferable to dmi-quirking our way out of this, since there are likely quite a few devices suffering from this. Signed-off-by: Hans de Goede Cc: Mark Salter Cc: Ard Biesheuvel Cc: Len Brown Cc: "Rafael J. Wysocki" Cc: Andy Shevchenko Cc: Peter Jones Signed-off-by: Matt Fleming Signed-off-by: Ard Biesheuvel --- drivers/firmware/efi/reboot.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) diff --git a/drivers/firmware/efi/reboot.c b/drivers/firmware/efi/reboot.c index 62ead9b9d871..7117e2d0c7f9 100644 --- a/drivers/firmware/efi/reboot.c +++ b/drivers/firmware/efi/reboot.c @@ -5,6 +5,8 @@ #include #include +void (*orig_pm_power_off)(void); + int efi_reboot_quirk_mode = -1; void efi_reboot(enum reboot_mode reboot_mode, const char *__unused) @@ -51,6 +53,12 @@ bool __weak efi_poweroff_required(void) static void efi_power_off(void) { efi.reset_system(EFI_RESET_SHUTDOWN, EFI_SUCCESS, 0, NULL); + /* + * The above call should not return, if it does fall back to + * the original power off method (typically ACPI poweroff). + */ + if (orig_pm_power_off) + orig_pm_power_off(); } static int __init efi_shutdown_init(void) @@ -58,8 +66,10 @@ static int __init efi_shutdown_init(void) if (!efi_enabled(EFI_RUNTIME_SERVICES)) return -ENODEV; - if (efi_poweroff_required()) + if (efi_poweroff_required()) { + orig_pm_power_off = pm_power_off; pm_power_off = efi_power_off; + } return 0; } -- 2.11.0