24-bit UAC2 support

[Sinister-Dexter]

Does anyone know how to get 24-bit 96khz output working with the UAC2 ?

I have the speaker example working on an STM32F746 with full-speed USB, this appears to work 24-bit 48khz, however not at 96khz.

Modifying the below in tusb_config.h for 24-bits :

// 16bit in 16bit slots - (now 24)
#define CFG_TUD_AUDIO_FUNC_1_N_BYTES_PER_SAMPLE_RX                   3
#define CFG_TUD_AUDIO_FUNC_1_RESOLUTION_RX                           24

fails when connected on the TU_ASSERT in dcd_dwc2.c as below -

// If size_rx needs to be extended check if there is enough free space
if (dwc2->grxfsiz < new_sz) {
TU_ASSERT(new_sz <= _dcd_data.dfifo_top);
dwc2->grxfsiz = new_sz; // Enlarge RX FIFO

new_sz is 320, dfifo_top is 304

Is there another define that needs to be changed or is this some other limitation?

Thanks