I recently upgraded my Dell E6410 with NVS 3100m GPU laptop from Ubuntu 10.10 (Maverick Meerkat) to 11.04 (Natty Narwhal), and I can’t shake this feeling that the distribution has taken a few steps back. I’m not even referring to the new Unity desktop, but to some super-irritating annoyances I had to fix or work around before being able to use the system. These annoyances were not present in 10.10, it had a whole different collection. 🙂
Wireless N connects, but no packets get through
The first annoyance was when I successfully connected to my wireless N access point, but couldn’t get a single packet through. After much searching, it turns out there’s a bug in the firmware for the Centrino Advanced-N 6200 wireless adapter that keeps it from getting any data through.
The solution is to disable wireless N on your laptop by creating a file etc/modprobe.d/inteldisablen.conf with the following contents:
options iwlagn 11n_disable50=1 11n_disable=1
and then to reboot. If you don’t want to reboot, just rmmod and modprobe the iwlagn kernel module. I’ve confirmed that this fix works.
Google Chrome scrolls excruciatingly slowly
After resuming and suspending, certain 2D and GPU-assisted graphics operations slow down. Scrolling in Chrome, even on a simple Google results page, is excruciatingly slow with head-explosion-levels of lag.
The solution is to disable hyperthreading, or at least to disable a number of CPU cores, at suspend and re-enable at resume. My laptop i5 CPU has 2 real cores, and thus 4 virtual cores due to hyperthreading. I’m using the following script, taken from this forum thread to do the necessary core disabling / enabling automatically:
#!/bin/sh # Disable hyper-threading processor cores on suspend and hibernate, re-enable them # on resume. Presumably helps for buggy nvidia behaviour. # save this file as /etc/pm/sleep.d/20_core_i5_disable_cores and make excutable # with chmod +x /etc/pm/sleep.d/20_core_i5_disable_cores # from: http://www.nvnews.net/vbulletin/showthread.php?t=158091 case $1 in hibernate|suspend) echo 0 > /sys/devices/system/cpu/cpu1/online echo 0 > /sys/devices/system/cpu/cpu3/online ;; thaw|resume) echo 1 > /sys/devices/system/cpu/cpu1/online echo 1 > /sys/devices/system/cpu/cpu3/online ;; esac
I’ve confirmed both the slow-down behaviour and the working of the fix.
Eclipse scrollbars don’t work
Natty’s new overlay scrollbars screw with Eclipse’s scrollbars, leaving you with 100% non-working scrollbars! You can either disable the overlay scrollbars completely, or comment out the GDK_NATIVE_WINDOWS line close to the start of the /usr/bin/eclipse shell script:
On my setup, this fix works most of the time.
It’s a shame that these things don’t work out of the box, as some of them had been reported long before the Natty release. Before I forget, if you install 11.04 on this specific laptop, you might also have to follow my Ubuntu 10.10 howto if you see a black screen at bootup or resume.