Difference between revisions of "Power management"
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===Enter suspend to memory mode (i.MX in Sleep mode)=== | ===Enter suspend to memory mode (i.MX in Sleep mode)=== | ||
| + | <pre class="target"> | ||
# echo mem > /sys/power/state | # echo mem > /sys/power/state | ||
| − | + | </pre> | |
| − | + | only an external interrupt can now wake up the i.MX27 | |
{{Warning| The mode 'mem' is not implemented in the kernel 2.6.35 for the [[APF28]]. please use the 'standby' mode}} | {{Warning| The mode 'mem' is not implemented in the kernel 2.6.35 for the [[APF28]]. please use the 'standby' mode}} | ||
| − | + | Only few interrupts can wake up the i.MX51 from this mode. please check the mx51 reference manual for further information. | |
===Wake up the board from sleep mode=== | ===Wake up the board from sleep mode=== | ||
Revision as of 17:28, 20 February 2013
Page under construction...
Informations on this page are not guaranteed !!
APF9328
APF9328 alone
Power consumption measurements have been done on an APF9328 board.
The results are available in the APF9328 datasheet.
APF9328 connected to a DevLight board
| Functionnality | power needed @ 5V | how to reduce it |
|---|---|---|
| FPGA | xxxmA | don't configure it |
| Ethernet | ifconfig eth0 down | |
| i.MXL (proc + SDRAM + Flash) | ||
| LCD | ||
APF27/APF28/APF51
Linux configuration
 |
Note: now done by default in latest apf kernel configs |
Power management options --->
[*] Power Management support
[*] Power Management Debug Support
[*] Verbose Power Management debugging
[*] Suspend to RAM and standby
[ ] Test suspend/resume and wakealarm during bootup
< > Advanced Power Management Emulation
For the apf27, power management handling is done in arch/arm/mach-mx2/pm_imx27.c
- if you put the APF27 in suspend mode, it could be interesting to be able to wake it with the "User button":
$ make linux-menuconfig
- if you put the APF28 in suspend mode, you can use the power button to wake up the board.
To know if driver is launched
# dmesg | grep Power Power Management for Freescale i.MX2x
Ethernet
for the APF27 the fec_old driver currently do not implement CONFIG_PM stuff...
Power-up
- ifconfig eth0 up
Power-down
- ifconfig eth0 down -->> ~ -400 mW
Other devices
Should comply to suspend/resume device drive mechanism.
List available suspend modes
# cat /sys/power/state standby mem
Enter standby mode (i.MX in Doze mode)
# echo standby > /sys/power/state PM: Syncing filesystems ... done. PM: Preparing system for standby sleep Freezing user space processes ... (elapsed 0.00 seconds) done. Freezing remaining freezable tasks ... (elapsed 0.00 seconds) done. PM: Entering standby sleep Suspending console(s) (use no_console_suspend to debug) imx-uart imx-uart.0: preparing suspend imx-uart imx-uart.2: preparing suspend mxc_nand mxc_nand.0: preparing suspend ...
Enter suspend to memory mode (i.MX in Sleep mode)
# echo mem > /sys/power/state
only an external interrupt can now wake up the i.MX27
 |
Warning: The mode 'mem' is not implemented in the kernel 2.6.35 for the APF28. please use the 'standby' mode |
Only few interrupts can wake up the i.MX51 from this mode. please check the mx51 reference manual for further information.
Wake up the board from sleep mode
- For the APF28 you can use the power button, any active interrupt or the RTC.
- For the APF27 you will have to use an external interrupt.
- For the APF51 the RTc or an external interrupt can wake up the board.
Debugging suspend/resume
- pass no_console_suspend as boot parameter:
BIOS> setenv extrabootargs no_console_suspend BIOS> boot
Known problems
- APF27 USB: usb cause system warning :
# echo standby > /sys/power/state PM: Syncing filesystems ... done. Freezing user space processes ... (elapsed 0.01 seconds) done. Freezing remaining freezable tasks ... (elapsed 0.00 seconds) done. ___ apf27_pm_suspend ___ apf27_pm_resume ------------[ cut here ]------------ WARNING: at kernel/hrtimer.c:625 hres_timers_resume+0x3c/0x60() hres_timers_resume() called with IRQs enabled!Modules linked in: gpio [<c002c0d8>] (dump_stack+0x0/0x14) from [<c003c148>] (warn_slowpath+0x70/0x8c) [<c003c0d8>] (warn_slowpath+0x0/0x8c) from [<c0055dfc>] (hres_timers_resume+0x3c/0x60)
