[mythtv-users] ACPI wakeup does not work

[Lawrence Rust]

On Thu, 2011-10-06 at 10:33 -0400, R KANNAN wrote:
> Hello,
> 
> I am trying to set up BIOS based wakeup on a Lenovo laptop running
> Mythbuntu 11.04  and I am following instructions on the following wiki
> page:
> 
> http://www.mythtv.org/wiki/ACPI_Wakeup#BIOS_setup
> 
> My BIOS time is set to local time and not UTC.  When I manually set up
> the alarm and test the wake up functionality, it does not work.
> 'cat /proc/driver/rtc' returns
> 
> rtc_time	: 10:21:32
> rtc_date	: 2011-10-06
> 
> alrm_time	: 10:30:00
> alrm_date	: 2011-10-06
> alarm_IRQ	: yes
> alrm_pending	: no
> 24hr		: yes
> periodic_IRQ	: no
> update_IRQ	: no
> HPET_emulated	: yes
> DST_enable	: no
> periodic_freq	: 1024
> batt_status	: okay
> The one difference I see from the wiki page is HPET_emulated changed
> to 'yes'. My bios does support this functionality as given by 'grep -i
> rtc /var/log/kern.log'
> 
> Any ideas?

Many BIOSes require HPET emulation to be disabled for RTC wakeup to
function.  If your BIOS setup doesn't provide an option then the Linux
kernel has a command line option to do so.  As root
change /etc/default/grub thus:
- GRUB_CMDLINE_LINUX=""
+ GRUB_CMDLINE_LINUX="hpet=disable i8042.noaux"

Save the file and then execute:
sudo update-grub

Re-boot and you should be OK.

-- 
Lawrence