Well, you never responded to my question about what DPP is, or where you're getting it from, so I have to still go with my original assumption that is it Windows software from the Canon CD
. The chances of it working really well
under Wine are unknown (to me, at this time). If Canon is going to support Linux, that is a question to be asked of Canon.
If it is a work-flow for RAW images you're looking for, there are many
native Linux applications that can handle RAW images, so it becomes a question of getting those images onto your PC. If you cannot transfer them directly from your camera (but can transfer the JPG images, I presume), then I still maintain that a card reader is going to be the easiest solution.
If you're happy with your current workflow with digiKam, then I guess that's it...
Sorry I couldn't be of more help.