On Mon, 09 Sep 2019 22:51:23 +0200, Arnd Bergmann wrote:
On Mon, Sep 9, 2019 at 10:39 PM Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com wrote:
On 9/9/19 2:51 PM, Arnd Bergmann wrote:
When CONFIG_SND_HDA_ALIGNED_MMIO is selected by another driver (i.e. Tegra) that selects CONFIG_SND_HDA_CORE as a loadable module, but SND_SOC_SOF_HDA_COMMON is built-in, we get a link failure from some functions that access the hda register:
sound/soc/sof/intel/hda.o: In function `hda_ipc_irq_dump': hda.c:(.text+0x784): undefined reference to `snd_hdac_aligned_read' sound/soc/sof/intel/hda-stream.o: In function `hda_dsp_stream_threaded_handler': hda-stream.c:(.text+0x12e4): undefined reference to `snd_hdac_aligned_read' hda-stream.c:(.text+0x12f8): undefined reference to `snd_hdac_aligned_write'
Add an explicit 'select' statement as a workaround. This is not a great solution, but it's the easiest way I could come up with.
Thanks for spotting this, I don't think anyone on the SOF team looked at this. Maybe we can filter with depends on !TEGRA or !SND_HDA_ALIGNED_MMIO at the SOF Intel top-level instead?
That doesn't sound much better than my approach, but could also work. One idea that I had but did not manage to implement was to move out the snd_hdac_aligned_read/write functions from the core hda code into a separate file. I think that would be the cleanest solution, as it decouples the problem from any drivers.
Yeah, that's a tricky problem because of the reverse-selection, as usual...
Another solution would be to just avoid byte/word access but use only long access, i.e. replace snd_hdac_chip_readb() with snd_hdac_chip_readl() with the aligned register and bit shift. The aligned access helper is needed only for the register that isn't aligned with 4 bytes offset.
And, one remaining question is whether it makes sense to enable CONFIG_SND_SOC_SOF_HDA without CONFIG_SND_HDA_EXT_CORE (that selects CONFIG_SND_HDA_CORE, too). Currently it seems conditionally selected, but many codes do depend on snd_hdac_ext_*() and other helper code with CONFIG_SND_SOC_SOF_HDA-ifdef.
thanks,
Takashi