Describe the bug
On Raspberry Pi 4, the vc4-hdmi driver does not expose any ALSA channel‑map (chmap) controls. As a result, user‑space applications cannot query or negotiate channel positions, and multichannel HDMI audio cannot follow industry‑standard channel order.
This affects all applications that rely on ALSA’s channel‑map API, including those that expect standard C/LFE ordering for 5.1 and 7.1 output.
I've had this problem on the Pi3 and Pi4. I've found ways to work around the issue on the Pi3. No workaround method has been found on the Pi4.
Steps to reproduce the behaviour
Playback a 5.1 (6 channel) multichannel file that follows the industry standard that has existed for decades now of front left, front right, center, lfe, rear left, rear right, using aplay (without specifying a channel order), and observe that playback swaps the center and lfe.
or
Setup plexamp, configure it to not downmix to stereo, playback multichannel audio, and hear the center and lfe being swapped.
Device (s)
Raspberry Pi 4 Mod. B
System
https://pastebin.com/vvUB3rjf
Logs
No response
Additional context
I've gotten the runaround everywhere I've gone to with this problem. I seem to be surrounded by people that ask themselves "how can I justify claiming this is someone else's problem" rather than "how can I fix this"? As someone that has prided themselves working many years in IT support, I've always gone with the 2nd question. Please don't be one of those many people that go with the first. I've put hours of testing, trial and error, and research into chasing this down.....I need to find other people that are willing to help, instead of just dismissing all my efforts.
Describe the bug
On Raspberry Pi 4, the vc4-hdmi driver does not expose any ALSA channel‑map (chmap) controls. As a result, user‑space applications cannot query or negotiate channel positions, and multichannel HDMI audio cannot follow industry‑standard channel order.
This affects all applications that rely on ALSA’s channel‑map API, including those that expect standard C/LFE ordering for 5.1 and 7.1 output.
I've had this problem on the Pi3 and Pi4. I've found ways to work around the issue on the Pi3. No workaround method has been found on the Pi4.
Steps to reproduce the behaviour
Playback a 5.1 (6 channel) multichannel file that follows the industry standard that has existed for decades now of front left, front right, center, lfe, rear left, rear right, using aplay (without specifying a channel order), and observe that playback swaps the center and lfe.
or
Setup plexamp, configure it to not downmix to stereo, playback multichannel audio, and hear the center and lfe being swapped.
Device (s)
Raspberry Pi 4 Mod. B
System
https://pastebin.com/vvUB3rjf
Logs
No response
Additional context
I've gotten the runaround everywhere I've gone to with this problem. I seem to be surrounded by people that ask themselves "how can I justify claiming this is someone else's problem" rather than "how can I fix this"? As someone that has prided themselves working many years in IT support, I've always gone with the 2nd question. Please don't be one of those many people that go with the first. I've put hours of testing, trial and error, and research into chasing this down.....I need to find other people that are willing to help, instead of just dismissing all my efforts.