Chris Brown All Smiles Arriving at Court to Fight Ex-Housekeeper's $90 Mil Lawsuit

Chris Brown is back in court for his battle with his former housekeeper -- who claims she was viciously mauled by a dog outside his L.A. home -- days after drama erupted in the case.

We got the singer as he walked into the courthouse Thursday for day one of his trial against Maria Avila ... he had few words for our photog, but his expressions when she asked him questions provided all the answers.

As TMZ first reported ... the trial was scheduled to start earlier this week, but a mistrial was called because one of the jurors had researched the case, which is against the rules.

When asked how he felt about the trial, Chris smiled and waved. The singer didn't seem too concerned about the $90 million Maria is seeking in damages over her alleged physical and emotional injuries.

Chris denies all allegations of wrongdoing and believes Maria provoked the dog, which led to the attack.

The entertainer and his former housekeeper are scheduled to testify during the trial.