Commit:
44be28e9dd ("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 <hdegoede@redhat.com>
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Signed-off-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Len Brown <lenb@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Salter <msalter@redhat.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@rjwysocki.net>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/20170818194947.19347-7-ard.biesheuvel@linaro.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The EFI capsule mechanism allows data blobs to be passed to the EFI
firmware. A common use case is performing firmware updates. This patch
just introduces the main infrastructure for interacting with the
firmware, and a driver that allows users to upload capsules will come
in a later patch.
Once a capsule has been passed to the firmware, the next reboot must
be performed using the ResetSystem() EFI runtime service, which may
involve overriding the reboot type specified by reboot=. This ensures
the reset value returned by QueryCapsuleCapabilities() is used to
reset the system, which is required for the capsule to be processed.
efi_capsule_pending() is provided for this purpose.
At the moment we only allow a single capsule blob to be sent to the
firmware despite the fact that UpdateCapsule() takes a 'CapsuleCount'
parameter. This simplifies the API and shouldn't result in any
downside since it is still possible to send multiple capsules by
repeatedly calling UpdateCapsule().
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Bryan O'Donoghue <pure.logic@nexus-software.ie>
Cc: Kweh Hock Leong <hock.leong.kweh@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Peter Jones <pjones@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: joeyli <jlee@suse.com>
Cc: linux-efi@vger.kernel.org
Link: http://lkml.kernel.org/r/1461614832-17633-28-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
It appears that the BayTrail-T class of hardware requires EFI in order
to powerdown and reboot and no other reliable method exists.
This quirk is generally applicable to all hardware that has the ACPI
Hardware Reduced bit set, since usually ACPI would be the preferred
method.
Cc: Len Brown <len.brown@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Not only can EfiResetSystem() be used to reboot, it can also be used to
power down machines.
By and large, this functionality doesn't work very well across the range
of EFI machines in the wild, so it should definitely only be used as a
last resort. In an ideal world, this wouldn't be needed at all.
Unfortunately, we're starting to see machines where EFI is the *only*
reliable way to power down, and nothing else, not PCI, not ACPI, works.
efi_poweroff_required() should be implemented on a per-architecture
basis, since exactly when we should be using EFI runtime services is a
platform-specific decision. There's no analogue for reboot because each
architecture handles reboot very differently - the x86 code in
particular is pretty complex.
Patches to enable this for specific classes of hardware will be
submitted separately.
Tested-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Implement efi_reboot(), which is really just a wrapper around the
EfiResetSystem() EFI runtime service, but it does at least allow us to
funnel all callers through a single location.
It also simplifies the callsites since users no longer need to check to
see whether EFI_RUNTIME_SERVICES are enabled.
Cc: Tony Luck <tony.luck@intel.com>
Tested-by: Mark Salter <msalter@redhat.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
Hans de Goede