The former Apple executive -- he left that company in 2006 -- has "no immediate plans," Arik Hesseldahl reports.
Rubinstein made his name revamping Palm from an aging business PDA manufacturer and BlackBerry rival into an accessible, consumer-focused player in the rapidly accelerating mobile space. (Before that, he worked on Apple's iPod.)
That trajectory, though spectacular in many ways, ended quietly when Palm failed to win consumers' hearts at the cash register.
Since then, it's been a series of false starts: HP has seen its own internal turmoil, with Palm caught right in the middle. Failed smartphones begot a failed tablet. With little to look forward to, it can't have been a difficult decision for Rubinstein to depart.
The move should be unsurprising; top executives often leave after a merger or acquisition. In many ways, it's remarkable that Rubinstein stayed at HP so long, though that may be more a reflection of the company's lack of preparation in the mobile space than anything else.
We don't know what Rubinstein's next move will be, but his final goodbye raises questions about HP's mobile strategy once again.