Re: [alsa-devel] [RFC PATCH 31/40] soundwire: intel: move shutdown() callback and don't export symbol

From: Pierre-Louis Bossart
Date: Fri Aug 02 2019 - 13:42:37 EST

On 8/2/19 12:28 PM, Vinod Koul wrote:
On 26-07-19, 09:46, Pierre-Louis Bossart wrote:

On 7/26/19 5:38 AM, Cezary Rojewski wrote:
On 2019-07-26 01:40, Pierre-Louis Bossart wrote:
+void intel_shutdown(struct snd_pcm_substream *substream,
+ÂÂÂÂÂÂÂÂÂÂÂ struct snd_soc_dai *dai)
+ÂÂÂ struct sdw_cdns_dma_data *dma;
+ÂÂÂ dma = snd_soc_dai_get_dma_data(dai, substream);
+ÂÂÂ if (!dma)
+ÂÂÂÂÂÂÂ return;
+ÂÂÂ snd_soc_dai_set_dma_data(dai, substream, NULL);
+ÂÂÂ kfree(dma);

Correct me if I'm wrong, but do we really need to _get_dma_ here?
_set_dma_ seems bulletproof, same for kfree.

I must admit I have no idea why we have a reference to DMAs here, this looks
like an abuse to store a dai-specific context, and the initial test looks
like copy-paste to detect invalid configs, as done in other callbacks. Vinod
and Sanyog might have more history than me here.

I dont see snd_soc_dai_set_dma_data() call for
sdw_cdns_dma_data so somthing is missing (at least in upstream code)

IIRC we should have a snd_soc_dai_set_dma_data() in alloc or some
initialization routine and we free it here.. Sanyog?

the code does a bunch of get_dma_data() and this seems to work, but indeed I don't see where the _set_dma_data() is done. magic.