Hi Fabio,
On Wed, Jan 08, 2014 at 01:50:45AM -0200, Fabio Estevam wrote:
In 3.12 and 3.13-rc we are able to play audio without using any SDMA firmware, but it we are not longer able to do this now. Other than that, people will have to use the exact 2.1 firmware version, so there will be a regression in 3.14, right?
I think it is impossible to run SDMA without firmware, which stores all the scripts we need, including Audio's one. Although the upstream kernel doesn't have firmware, the reason why you were able to run audio playback is because you have the firmware in your rootfs. So since the driver's upgraded, it's plausible for us to upgrade the firmware as well. But I do agree the way we handle the old version while trying to use the new script isn't professional. Ideally we should switch the script to the old one if we find the firmware version is 1.1. But technically it's hard to achieve that since we assign the script in DT.
So currently if people are gonna use 3.14, they might need to upgrade their firmware as you just tried to your rootfs.
Couldn't we keep the 3.12/3.13 behaviour, ie, be able to play audio without loading any SDMA firmware?
There are two ways to keep it as the old one. First is patching the SDMA firmware patch, including v2, to upstream kernel. And the second is to revert the patch (ARM: dts: imx: use dual-fifo sdma script for ssi) so that the SSI driver and SDMA driver would continue to use the old single FIFO mode.
I'll align this issue with Shawn first to see if there's a better solution.
Thank you, Nicolin Chen