Probable cause of "exigent circumstances" as a valid reason to search a house without a warrant is settled law - nothing new. If the court found probable cause, then, again this is nothing new.
Not sure what the "qualified immunity" part is about though.
Under a long line of Supreme Court cases, if you sue the cops for money damages for violating your constitutional rights, the cops have "qualified immunity" from paying damages unless it was clear that what they did was illegal. The idea is that cops shouldn't pay damages if what they did was in a gray area, even if it turns out later that the court finds their actions illegal.
Here, the court said that it was a gray area whether the "exigent circumstances" exception to the warrant requirement applied.