SysRq and Inspiron 1720

While trying to figure out while my laptop, a Dell Inspiron 1720, has been freezing occasionally, I found out that you can use SysRq codes to communicate directly with the Linux kernel to get system operations done even while the machine is locked up. This is handy as it allows you to specify a sequence of actions to safely sync your disks prior to rebooting your computer. Then you don’t have to go through the trouble of running fsck on your filesystems.

The typical sequence that you are told to input is to hold down Alt+SysRq and then slowly type r e i s u b. This presents a slight problem on the Inspiron 1720 since the SysRq key is shared with F11. Accessing the SysRq key requires pressing the Fn key but you must not have the Fn key depressed while you type the subsequent letters or they are interpreted as something different. I have found the easiest way to perform this magical little finger dance is to use your right hand to press the right Alt key with your thumb and the SysRq with a finger. So the sequence is:

Left hand: Press and hold “Fn” key (between Ctrl and the Windows key)
Right hand: Press and hold “Alt” + “SysRq” keys (Alt+F11)
Left hand: Release “Fn” key
Left hand: Press and release “r” key. (Screenshot dialogs may start popping up. Ignore them)
Left hand: Press and release “e” key. (Your GUI should collapse to a tty, most processes terminated)
Left hand: Press and release “i” key. (Progress of key shown in the tty, most proceses killed)
Left hand: Press and release “s” key. (Progress of key shown in the tty, syncs filesystems)
Left hand: Press and release “u” key. (Progress of key shown in the tty, unmounts filesystems)
Left hand: Press and release “b” key. (Progress of key shown in the tty, starts reboot)
Right hand: Release all keys

Wifi Killswitch does not enable Wifi

Over the past couple of days, I have seen a situation where I boot my laptop (Ubuntu Karmic) and the Network Manager applet insists that the wireless is disabled. Rebooting does not help. Examining the syslog showed that the OS found 2 kill switches and one of them was disabling the wireless. Examining the state showed that each kill switch state was affected by the single physical kill switch, but their states were the opposite of each other. So regardless of which position the kill switch is in, one of the kill switch devices would disable the wireless.

I turned the kill switch off and reboot the computer. When it came up, the kill switch drivers were now synchronized and turning the kill switch on caused the Network Manager to start looking for Wireless connections. Listing the kill switch states shows they are again synchronized.

This post at LinuxTrap shows that others are experiencing a similar condition.

VGA and S-Video output on an Inspiron 1720 in Ubuntu

Note these instructions are for Ubuntu 9.10 (Karmic).

In prior versions of Ubuntu, I have had some problems getting the VGA and S-Video outputs on my Inspiron 1720 working, so today I tackled this problem. In Karmic, this process is quite straightforward. Once you connect your video cable to the laptop, whether it is S-Video to a television or VGA to a monitor, you can cycle through various video distribution modes using the Fn-F8 keys. This is marked as “CRT/LCD” on the F8 key. Here is the cycle that I found using S-Video output.

1. LCD on at full resolution ; TV off
2. LCD off ; TV on at 848×480
3. LCD on at full resolution ; TV on and to right of LCD, 848×480 ; desktop shared across both screens
4. LCD on, 1024×768 ; TV on, 1024×768 ; mirrored desktop

You can change the parameters of each of these cycles by running the Display Preferences applet (System->Preferences->Display). This applet has a spacial depiction of  both displays and you may drag a display to be in a specific location with respect to the other display. For example, if in 3 above, you wanted the TV to appear logically above the CRT, you would drag the TV rectangle (labeled “unknown” for me) above the rectangle labeled “Laptop 17”.

Mode 3 shares the desktop over the 2 screens so that you can move the mouse cursor from one screen to the other screen, effectively extending your desktop. If you use an image as your desktop background, you may get the background color showing around the edges of the image as the image is centered in the extended display resolution.

Mode 4 shows the same content on the laptop LCD panel as on the connected screen. Note that in this mode for a connected television, the video quality is less crisp than in mode 3 due to the scaling of the 1024×768 resolution to something the television can handle.

If you connect a VGA cable to a monitor, a similar cycle is used, but the VGA resolutions used will be different.

Out of curiosity, I connected both a VGA monitor and S-Video to the TV, but preference seems to be given to the VGA monitor such that the TV never gets a signal.

Hard Drive failure

Both JP and I have experienced hard drive failures on the laptop just outside of the warrenty period. The new drives (not from Dell) have been working fine and require less power.

Strike Zone on bottom of laptop

Strike Zone Hard Drive Protection System
The Strike Zone Hard Drive ProtectionTM system was designed and developed by Dell to protect your Latitude from damage and potential loss of important business data. Using a resonant vibration damper, Strike Zone helps absorb the shock, dispersing energy away from your hard drive in the event of accidental laptop drops and bumps.

6Gb Laptop RAM

It looks like, contrary to what Dell says, the Inspiron 1720 will
support 6Gb of RAM (4+2).  The chipset actually supports 8Gb but a bug
in BIOS prevents it from being loaded up with 8Gb.

LCD and Keyboard

LCD panel failed and keyboard is flakey. Debugging over the phone with Dell tech support, opened up the laptop and reseated the LCD and keyboard panels but this did no good. Returned laptop to Dell and it came back with everything working fine.

Memory (RAM)

2Gb is not really enough memory if you are doing any sort of Java development and you tend to open multiple copies of Eclipse.

4Gb is better, but unless you are running a 64bit OS, there is a significant amount of the address space that is eaten up my memory mapped IO, resulting in only effectively 3.2Gb or so.

Triple Boot 2

Ok, I have got this thing triple booting Media Direct, Vista and Ubuntu.

Roughly, the steps are.

– Do Media Direct prep install (boot from the disk and follow instructions). Make 2 partitons, the first for Vista, the second will be repartitioned later for Ubuntu.
– Start Vista install, Do AHCI driver install during Vista install. Finish Vista install onto the partition set up during Media Direct prep
– Finish Media Direct install
– Install Ubuntu. Do manual partitioning. Delete 2nd partition that was set up during Media Direct prep. Create Ubuntu partitions as required.

For example a primary partition for Ubuntu of 30Gb, ext3, mount point /
an extended partition of 60Gb, ext3, mount point /home
an extended partition of 3.4Gb, swap

Choose to install grub in the ubuntu partition which is (hd0,3) in my case instead of the MBR (hd0)

If you want Windows to boot by default
– chain grub into the Vista bootloader. Download and install easybcd and set up a bootloader entry for ubuntu.
If you want Ubuntu to boot by default
– Boot ubuntu, run fdisk and clear the boot flag from the Windows partition and set it on the primary Ubuntu partition. Vista is already set up in Grub.