XO1.5 SD suspend: Difference between revisions
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===Exploring from Open Firmware=== |
===Exploring from Open Firmware=== |
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While we are mainly dropping into OFW on suspend and resume in order to allow for orderly testing, it is possible to explore the state of hardware registers or manually trigger a suspend (without returning to Linux). |
While we are mainly dropping into OFW on suspend and resume in order to allow for orderly testing (OFW by default ignores SCI wakeup events, which tend to wake Linux at random times), it is possible to explore the state of hardware registers or manually trigger a suspend (without returning to Linux). |
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You can set up to examine registers in the SD controller using these commands: |
You can set up to examine registers in the SD controller using these commands: |
Revision as of 04:00, 1 October 2009
This describes the current setup for testing WLAN SD suspend/resume on prototypes of the XO-1.5 laptop.
Software Installation
You should start by obtaining the OS31 Linux image for the XO-1.5 from http://dev.laptop.org/~cjb/f11-1.5/os31/os31.zd.
- Place the image on a USB stick, and insert it into the XO-1.5 laptop's USB port.
- Boot the laptop, pressing the escape key ('X' in upper left hand corner of keyboard) within a few seconds after boot to enter Open Firmware (OFW).
- To install onto the internal SD card, type:
fs-update u:\os31.zd
Now upgrade the kernel to one supporting Marvell's SD patches. The following sequence of commands should work:
wget http://dev.laptop.org/~dilinger/olpc-2.6.30/kernel-2.6.30_xo1.5-20090919.0127.1.olpc.d2189d4.i586.rpm wget http://dev.laptop.org/~dilinger/olpc-2.6.30/kernel-firmware-2.6.30_xo1.5-20090919.0127.1.olpc.d2189d4.i586.rpm wget http://dev.laptop.org/~cjb/marvell-sd.tar rpm -ivh kernel-* tar xvf marvell-sd.tar mv nico-plus-ofw-drop /boot/vmlinuz mv lib80211.ko /lib/modules/kernel*d218*/net/wireless/ mv *.ko /lib/modules/kernel*d218*/drivers/net/wireless/libertas reboot
Hardware Modification
In order to disconnect the SD_PWOFF signal, preventing it from powering off the WLAN card in suspend, you should remove Q38. This is in an SOT-323 package, located on the "bottom" side of the motherboard (the same side as the processor) right below the WLAN card connector.
You will also need to connect a serial terminal, as the laptop display doesn't work after resume. It should be connected to J3, and JP1 (immediately behind J3) will need pin 1 shorted to pin 3 to enable the serial port.
Test Procedure
If modified by removing Q38, the laptop must be powered down to power cycle the WLAN (not rebooted).
Boot the laptop. Due to a problem with OS31, it will halt in Open Firmware. Boot Linux by typing:
boot int:\olpc.fth
When Linux has booted, you can place the system into suspend by typing:
echo mem > /sys/power/state
This will complete the Linux suspend operations (calling all drivers), the drop the system into OFW right before actually suspending the hardware. You should see the "ok" prompt, although it may take a few seconds if there are filesystem modifications that have to be flushed to non-volatile storage.
All commands after this HAVE to be typed through the serial port.
In order to actually finish suspending the system, type:
resume
In order to wake the laptop from suspend, press the power button. This will bring you back to an OFW prompt ("+rok"). In order to start Linux executing again, type "resume" one more time. This should bring you back to a Linux prompt.
Exploring from Open Firmware
While we are mainly dropping into OFW on suspend and resume in order to allow for orderly testing (OFW by default ignores SCI wakeup events, which tend to wake Linux at random times), it is possible to explore the state of hardware registers or manually trigger a suspend (without returning to Linux).
You can set up to examine registers in the SD controller using these commands:
ok select /sd 0 3 set-address map-regs
Now you can read the contents of the registers using the cw@ (config-word-read) command (which takes a register offset from the stack as an argument):
ok 2c cw@ .
You can modify the contents of a register using the cw! (config-word-write) command (which takes a register offset and a value from the stack as arguments).
In order to manually trigger a suspend, type:
ok select /wlan ok 2400 404 pw!
Monitoring
The signals to the WLAN card may easily be probed at the WLAN connector:
- SD_CLK
- WLAN_3.3V
- SD_CMD
- GND
- SD_DAT0
- RESET#
- SD_DAT1
- N.C.
- SD_DAT2
- POWER_DOWN#
- CARD_DETECT#
- N.C.
- SD_DAT3
- ...
The signals on odd pins are accessible from the "bottom" side of the motherboard (the side with the processor). The signals on even pins are only accessible from the top side of the motherboard.