Linux Kernel 2.6.36 on the HP Pavilion DV8T

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I’ve been running Ubuntu 10.04 on my Pavilion DV8T since it landed on my desk earlier this year. All the important things work, but there were two minor bits of missing functionality and one annoying bug:

  • No working temperature sensors (the hard drive doesn’t count!)
  • ACPI won’t report battery charge/discharge rate
  • ALSA randomly stops making noise after a while

I’ve been running a 2.6.35 kernel ever since I started using btrfs as my root file system but it didn’t help with any of these three problems.

Some Improvements Since Upgrading to 2.6.36

I built myself a 2.6.36-rc5-git6 kernel a few days ago. I can now get a temperature readout from ACPI, but I think it is very inaccurate. I am seeing 134°F when the fan is off, and I’ve seen it read as high as 185°F under moderate load. The laptop never feels hot enough for me to believe either number.

I hope I’m not speaking too soon here, but my sound has been working perfectly for at least four days so far. I’m hoping that I will never have to run my ALSA unload/reload script again.

ACPI still doesn’t report the charge/discharge rate. This makes powertop a little less useful.

I’ve also noticed that powertop is showing that my wake-ups per second during idle are a bit lower. My usual “idle” workload when I’m on battery includes Chromium (with a few tabs open), claws-mail, emacs, and Pidgin sitting around doing nothing while I’m connected to Wi-Fi. With 2.6.35 it was rare to see anything less than 70 wake-ups per second. The last few days I’ve been seeing lots of mid 50s to low 60s with 2.6.36.

I haven’t been on battery enough to determine if there is any improvement in off-power runtime. So far, it looks like I’ll be getting the same 2.5 hours on battery as I always do.