On 5/24/23 13:39, Mark Brown wrote: > On Wed, May 24, 2023 at 10:41:56AM +0300, Cristian Ciocaltea wrote: >> The I2S0_8CH_MCLKOUT clock rate on Rock 5B board defaults to 12 MHz and >> it is used to provide the master clock (MCLK) for the ES8316 audio >> codec. >> >> On sound card initialization, this limits the allowed sample rates >> according to the MCLK/LRCK ratios supported by the codec, which results >> in the following non-standard rates: 15625, 30000, 31250, 46875. >> >> Hence, the very first access of the sound card fails: >> >> Broken configuration for playback: no configurations available: Invalid argument >> Setting of hwparams failed: Invalid argument >> >> However, all subsequent attempts will succeed, as the audio graph card >> will request a correct clock frequency, based on the stream sample rate >> and the multiplication factor. >> >> Assign MCLK to 12.288 MHz, which allows the codec to advertise most of >> the standard sample rates. > > Surely this is irrelevant with your previous change, and if the clock is > freely reprogrammable as it sounds even harmful given that it'll > restrict rates that are not available with the selected MCLK? As mentioned in the previous patch description, there's a bad timing with es8316_pcm_startup() being executed before the 2nd call to es8316_set_dai_sysclk(), with the effect that the new/updated rate constraints won't be used until the next playback attempt. Hence the approach here was to ensure the initial list of restricted rates is sane, by (pre)assigning a proper MCLK. Alternatively, we could have used an unsupported MCLK and, with the help of the previous patch, we would have ended up with no restrictions applied on es8316_pcm_startup().
