Problems with ACPI suspend-to-ram
The following glitches may or may not occur in relation to suspending to RAM:
Troubles on suspend
- Permissions
- If your suspend is failing, and a
# tail /var/log/acpid
shows "Permission denied" errors, be sure that your new ACPI event and action scripts have the appropriate permissions.
- Broken sysfs interface
- You may experience problems when using
# echo standby > /sys/power/state
or# echo mem > /sys/power/state
(machine goes to sleep and wakes up immediately). This can be avoided by using# echo -n 3 >/proc/acpi/sleep
to get it to sleep. This can be also happen if hotplug daemon is still running.
- MySQL daemon running
- If you're running MySQL, sleep may also not work, so stop MySQL first, then sleep. Remember to restart MySQL when you wakeup.
- LCD backlight remains on during sleep
- When your system is equiped with a Radeon Mobility graphic controller your LCD backlight may not turn off automatically. Use radeontool to switch off your backlight prior suspend in your sleep action script.
- High power drain during sleep
- Also, you might want to take note of the Problem with high power drain in ACPI sleep.
Troubles on resume
- Blank display on resume
- When resuming from a suspend-to-ram the display might remain black or might only show the pre-suspend output (the system is still rebootable via ctrlaltdel). Look here for solutions.
- Broken hardware support after resume
-
- The serial port of the port replicator might not work after resume.
- The parallel port might not work after resume. A possible fix is to unload and reload the parallel port drivers:
# rmmod lp parport_pc parport; modprobe lp
. - Problems with the CD-RW/DVD drive after wake up from ram have been experienced.
- There is a known Problem regarding battery info after suspend to RAM. A small patch exists for kernels 2.6.14/2.6.15.
- On X20 and X21 (and possibly other) models, the sleep LED is not reset properly on resume and will keep blinking. If you have the ibm-acpi kernel module loaded with the experimental=1 option, you can switch it off on resume by appending the following line to your suspend script:
echo 7 off > /proc/acpi/ibm/led
- Crash on resume
-
- When using older ATI proprietary drivers a crash on resume can be solved by using vbetool. An example suspend script can be found here. This is no longer necessary with recent revisions of the ATI proprietary driver.
- A crash could also be caused by having apic support enabled in the kernel config. Try disabling it (in the "Processor type and features" section).
- On machines with Savage chipsets, the savagefb framebuffer driver might crash the machine on resume. Make sure it is disabled in your kernel config and use the standard vesafb driver instead.
- Due to the fact that Sonoma chipset based laptops (R52, T43, T43p, X41, X41 Tablet) utilize the SATA layer for disk access and SATA does not have power-management support yet Suspend to RAM does these machines on resume. See the according section on the Problems with SATA and Linux page.