Re: [PATCH v2 2/3] ASoC: qcom: q6apm-dai: add VMID-based SCM assignment for mDSP buffers
Mark Brown <[email protected]>
| Newsgroups | gmane.linux.sound,gmane.linux.ports.arm.msm,gmane.linux.drivers.devicetree,gmane.linux.kernel |
|---|---|
| Message-ID | <[email protected]> |
On Wed, Aug 26, 2026 at 12:10:13AM +0530, Ajay Kumar Nandam wrote: > On platforms such as Qualcomm Shikra, audio is served by the modem DSP > (mDSP) which runs in a stage-2 protected context. Unlike ADSP targets > where SMMU-mapped system RAM is directly accessible, the mDSP cannot > reach the PCM buffers unless they are explicitly SCM-assigned to the > appropriate Virtual Machine IDs (VMIDs). Without this assignment, audio > does not function on these platforms. > - ret = snd_pcm_set_fixed_buffer_all(pcm, SNDRV_DMA_TYPE_DEV, component->dev, size); > + if (pdata->has_reserved_mem) > + ret = snd_pcm_set_managed_buffer_all(pcm, > + SNDRV_DMA_TYPE_DEV, component->dev, > + pdata->reserved_buf_size, > + pdata->reserved_buf_size); Does this do the right thing if the ALSA core preallocate_dma module param is set to 0 for some reason? I'm not clear why you would...
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