Hi,
On 22-06-17 11:55, Matt Fleming wrote:
On Wed, 21 Jun, at 03:15:09PM, Hans de Goede wrote:
HI,
On 23-04-17 14:36, Hans de Goede wrote:
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.
Cc: Mark Salter <msalter@xxxxxxxxxx>
Signed-off-by: Hans de Goede <hdegoede@xxxxxxxxxx>
What is the status of this patch ? It has had 2 somewhat favorable
reviews and then things went silent ?
Sorry about the delay. I've picked this up for the efi-next branch
since we're at -rc6 and it doesn't look like an -rc6-urgent bug.
Ack, putting this in -next is the right thing to do, you never know
what weird firmware quirks this patch may trigger. E.g. EFI_RESET_SHUTDOWN
could return on some models with the PMIC turned off leaving the device
running for XX ms on its power-supply capacitors, and then calling into
the ACPI method may cause weirdness.
Regards,
Hans
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