https://www.qantasnewsroom.com.au/qa...-perth-sydney/
I can't find any info on what actually went wrong (did one or both packs fail?) but they got the packs working again at 10,000 feet
This is probably a non-event but some media have dramatized it
to the extent of saying that passengers were writing final letters to loved ones. Indeed one person fainted, but maybe because of (unfounded) anxiety.
Here is an example
Woman faints and passengers scramble for oxygen masks as Qantas flight makes emergency landing | Daily Mail Online
I'm not too familiar with the Airbus systems, can the APU be used for pressurization in flight if both packs failed?