On Thu, Jun 29, 2023 at 06:33:09PM +0100, Srinivas Kandagatla wrote:
On 29/06/2023 16:43, Mark Brown wrote:
On Wed, Jun 28, 2023 at 10:24:04AM +0100, Srinivas Kandagatla wrote:
For some reason we ended up with a setup without this flag. This resulted in inconsistent sound card devices numbers which are also not starting as expected at dai_link->id. (Ex: MultiMedia1 pcm ended up with device number 4 instead of 0)
Why is this a problem?
In existing Qualcomm setup the backend pcm are added first, which results in frontend pcms getting pcm numbers after this.
For example: with 3 backend dailinks in DT we have frontend pcm start at 3. Now if we add new backend dai-link in DT we now have frontend pcm start at 4.
This is a bug in qualcomm driver.
Why is this an actual problem rather than just being a bit ugly? What is the negative consequence of having a PCM with this number?
With this patch patch now the MultiMedia1 PCM ends up with device number 0 as expected.
Fixes: 9b4fe0f1cd79 ("ASoC: qdsp6: audioreach: add q6apm-dai support") Cc: Stable@vger.kernel.org
Won't this be an ABI change? That seems like it'd disrupt things in stable.
Yes, but this is a real bug. without fixing this also results in abi(pcm number) change when we add new backend dai-link. I have also sent fix for UCM to handle this.
I'm still not clear why you believe this to be a bug.