HP Pavilion dv6820 is very similar to dv6650eg. I Think Pardus will work on it too, like my one.
My sister is using dv6010ea, where Pardus 2007.3 supports 100% the hardware of this laptop, but on my laptop Pardus does not support all. ACPI Buttons (the blue multimedia keys -> HP QuickPlay Keys between display and keyboard) and currently brightness control on Pardus 2007.3:
In the german PCLinuxOS Forum a member of our Core Team solved this problem on his Acer Laptop by some modifications and shell scripts ...
So I think it should be possible on HP Laptops too. I'm going to try the same method on my laptop with Pardus. If it does, than I'll let you know about that.
I hope that theses problems will be solved in Pardus 2008 - I love Pardus Linux (and of course honey PCLinuxOS)
Enjoy your new Laptop
With best regards