I use kde 4.3 rc3 via kubuntu karmic alpha3.

I have a 320 GB USB drive which has about 200 GB data.
When I mount my drive, either clicking on Device Notifier applet or by dolphin Places, plasma panel freezes for a few seconds, ie until the drive is opened in dolphin it freezes the panel and everything goes back to normal once dolphin opens the drive.

Its the same if I mount manually using mount command. Plasma freezes for a few seconds, during which
1. system tray works.
2. no other applets in plasma works - eg, desktop switcher, task manager.
3. alt-tab switching of applications work.

If you remove the device notifier, does this occur?

bcooksley wrote:If you remove the device notifier, does this occur?

I believe its not related to device notifier.
I removed Device Notifier. Mounted from konsole. After 2 seconds it freezes the plasma panel. I dont even have any dolphin or anything running. But the device is properly mounted. I opened a movie in the drive with mplayer when the plasma panel was in a frozen state.

So my guess some process related to plasma is reading something from the device which freezes it.

One side effect of this bug is any notifications which appear during that time,
like a chat message received in kopete during this time stays in notification
area itself.

Which Plasmoids do you have loaded in Plasma?

bcooksley wrote:Which Plasmoids do you have loaded in Plasma?

Folder View(showing desktop),notes, dictionary, desktop switcher, system tray, power devil, calender, show desktop, k menu

Does this also happen under a new user?

Figured out the reason for plasma freeze. Removing Application launcher(K-menu) fixed the plasma freezing part. But still if I use dolphin to mount , dolphin still takes the same time to open. It wil be in a frozen state.
while I can use konsole to view the files in the disk.

I tested on a new account. Plasma freeze is still there but dolphin opens instantaneously. Guess something is different.

Unfortunately I do not know the source of the problem, but it is likely related to Solid, in particular the HAL hardware backend.