Sunday, February 14, 2010

Slow HD due to CD polling

Original post date: Sat Nov 04 12:00:00 2006
Yesterday I upgraded our Dell Latitude to FC6, it was running FC4 and it was getting difficult to encounter some of the packages that I use on the desktop system (like Twinkle for example).
Well I can tell you that the installation went a whole lot better compared to the problems I had with the desktop machine!
There was just one thing that bothered me. Where the desktop actually seemed faster (as it was supposed to according to this, see the Performance section) the latop felt sluggish somehow. Applications were taking too long to load. When I tried measuring the drive's performance I got this:

which is way too slow for that drive. Then I remembered that I had the same problem before with this laptop and it was because of the polling KDED did of the CD rom drive (to detect media changes and such). Stopping KDED (which you can do in the KDE Control Center -> KDE Components -> Service Manager) would solve the problem.But with FC6 this didn't seem to help. I found an option called Enable CD polling in the Peripherals -> Storage Media of the Control Center, but the option was grayed out so I couldn't change it.
I finally found out today that it is HAL which does the polling nowadays, specifically the hald-addon-storage module. Killing it restored the expected performance:

So now it was time to figure out if something could be done about it. According to to this forum message it is a known problem with Dell laptops but it seems that the blacklisting it talks about doesn't work (anymore) in FC6.In the end I found out that HAL uses a set of rules to determine what to do with certain hardware which are stored in/usr/share/hal/fdi. By doing a lshal I could get a list of all the detected devices and find the information about the particular CD drive used in the laptop:

Using the information above I created my own fdi file information/30private/10-crappy-dell-cddrive.fdi with the following rules:



service haldaemon restart) everything was back to normal. Of course the system won't automatically detect any CDs being inserted into the drive, but I can live with that. (And yes, of course I filed a bug report)

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