"Chaithrika U S" <[email protected]> writes: > Kevin, > > With the cpufreq support on DA850/OMAP-L138 SoC we are observing > that audio does not function as expected at all sampling rates > for various operating points. At a CPU frequency of 96MHz, audio > works fine with a sampling frequency of 8kHz. For other sampling > rates, there are lot of underrun/overrun errors. This is because > of EDMA also runs at a lower speed and is not able to transfer > data at the desired rate. > > To overcome the above, we can depend on the user to set the scaling > min frequency to be the same as scaling max frequency (in this case > 300 MHz) before starting aplay/arecord or temporarily move to > performance governor so that the audio quality is not affected. > > Do you think this is the right approach to this problem? Any other > solutions you suggest exploring?
An alternative to relying on the user to change the CPUfreq policy is to have the audio driver itself do that. Based on the sample rate and clock frequency, the audio driver should be able to determine that the EDMA rate will not be fast enough and set a CPUfreq policy so that lower frequencies are not attempted. When the audio driver is done, it can set the policy back. Kevin _______________________________________________ Davinci-linux-open-source mailing list [email protected] http://linux.davincidsp.com/mailman/listinfo/davinci-linux-open-source
