| Message ID | 20190909195159.3326134-1-arnd@arndb.de |
|---|---|
| State | New |
| Headers | show |
| Series | ASoC: SOF: Intel: work around snd_hdac_aligned_read link failure | expand |
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? If you can share your config off-list I can try to simplify this further. > > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > --- > sound/soc/sof/intel/Kconfig | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/sound/soc/sof/intel/Kconfig b/sound/soc/sof/intel/Kconfig > index 479ba249e219..9180184026e1 100644 > --- a/sound/soc/sof/intel/Kconfig > +++ b/sound/soc/sof/intel/Kconfig > @@ -248,6 +248,7 @@ config SND_SOC_SOF_HDA_COMMON > tristate > select SND_SOC_SOF_INTEL_COMMON > select SND_SOC_SOF_HDA_LINK_BASELINE > + select SND_HDA_CORE if SND_HDA_ALIGNED_MMIO > help > This option is not user-selectable but automagically handled by > 'select' statements at a higher level >
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. > If you can share your config off-list I can try to simplify this further. I uploaded the .config to https://pastebin.com/raw/RMBGXTky for reference now. This is with the latest linux-next kernel, plus a series of patches that I keep around for fixing other build problems. Arnd
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
On Tue, Sep 10, 2019 at 9:06 AM Takashi Iwai <tiwai@suse.de> wrote: > 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. Ok, so basically open-coding the aligned access to RIRBSTS? That sounds like a much nicer workaround. So in place of sd_status = snd_hdac_stream_readb(s, SD_STS); dev_vdbg(bus->dev, "stream %d status 0x%x\n", s->index, sd_status); snd_hdac_stream_writeb(s, SD_STS, sd_status); I suppose one could just readl/writel SOF_HDA_ADSP_REG_CL_SD_CTL and print the shifted value, right? While I know nothing about the underlying requirements, I wonder about two things that stick out to me: 1. the existing code just writes back the same byte it has read. If this write has no side-effects, why write it at all? OTOH, if it has side-effects, isn't the aligned implementation of writing the whole word in snd_hdac_aligned_write() fundamentally flawed? 2. Doesn't the read-modify-write cycle in snd_hdac_aligned_write() need locking to work correctly? Arnd
On Tue, 10 Sep 2019 09:52:13 +0200, Arnd Bergmann wrote: > > On Tue, Sep 10, 2019 at 9:06 AM Takashi Iwai <tiwai@suse.de> wrote: > > 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. > > Ok, so basically open-coding the aligned access to RIRBSTS? > That sounds like a much nicer workaround. So in place of > > sd_status = snd_hdac_stream_readb(s, SD_STS); > dev_vdbg(bus->dev, "stream %d status 0x%x\n", > s->index, sd_status); > snd_hdac_stream_writeb(s, SD_STS, sd_status); > > I suppose one could just readl/writel SOF_HDA_ADSP_REG_CL_SD_CTL > and print the shifted value, right? Yes. > While I know nothing about the underlying requirements, I wonder > about two things that stick out to me: > > 1. the existing code just writes back the same byte it has read. If > this write has no side-effects, why write it at all? OTOH, if it has > side-effects, isn't the aligned implementation of writing the whole > word in snd_hdac_aligned_write() fundamentally flawed? The aligned read/write does already the whole 4-bytes read/write, so it should work. But we need confirmation with the actual hardware. > 2. Doesn't the read-modify-write cycle in snd_hdac_aligned_write() > need locking to work correctly? The helper doesn't guarantee the atomic write by itself, so a lock would be required in the caller side if needed. Luckily there aren't many places calling the unaligned access. thanks, Takashi
diff --git a/sound/soc/sof/intel/Kconfig b/sound/soc/sof/intel/Kconfig index 479ba249e219..9180184026e1 100644 --- a/sound/soc/sof/intel/Kconfig +++ b/sound/soc/sof/intel/Kconfig @@ -248,6 +248,7 @@ config SND_SOC_SOF_HDA_COMMON tristate select SND_SOC_SOF_INTEL_COMMON select SND_SOC_SOF_HDA_LINK_BASELINE + select SND_HDA_CORE if SND_HDA_ALIGNED_MMIO help This option is not user-selectable but automagically handled by 'select' statements at a higher level
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. Signed-off-by: Arnd Bergmann <arnd@arndb.de> --- sound/soc/sof/intel/Kconfig | 1 + 1 file changed, 1 insertion(+) -- 2.20.0