Re: [PATCH v11 0/7] Qualcomm's lpass-hdmi ASoC driver to support audio over dp port

[Stephan Gerhold]

Hi Srinivas,

On Thu, Oct 08, 2020 at 06:37:40AM +0100, Srinivas Kandagatla wrote:
> On 08/10/2020 06:16, Srinivasa Rao Mandadapu wrote:
> > These patches are to support audio over DP port on Qualcomm's SC7180 LPASS
> > Asoc. It includes machine driver, cpu driver, platform driver updates for
> > HDMI path support, device tree documention, lpass variant structure
> > optimization and configuration changes.
> > These patches depends on the DP patch series
> > https://patchwork.kernel.org/project/dri-devel/list/?series=332029
> > https://lore.kernel.org/patchwork/project/lkml/list/?series=464856
> > 
> > changes since V10:
> >      -- Moved hdmi regmap functions from lpass-hdmi.c to lpass-cpu.c
> >      -- Moved QCOM_REGMAP_FIELD_ALLOC macro from lpass-hdmi.c to lpass.h
> > changes since V9:
> >      -- Removed unused structures lpass_hdmi.h
> > changes since V8:
> >      -- Removed redundant structure wrapper for reg map field memebrs
> >      -- Updated lpass_hdmi_regmap_volatile API with appropriate registers as true
> >         and others as false.
> > changes since V7:
> >      -- Fixed typo errors
> >      -- Created Separate patch for buffer size change
> > changes since V6:
> >      -- Removed compile time define flag, which used for enabling
> >       HDMI code, based on corresponding config param is included.
> >      -- Updated reg map alloc API with reg map bulk API.
> >      -- Removed unnecessary line splits
> > changes since V5:
> >      -- Removed unused struct regmap *map in lpass_platform_alloc_hdmidmactl_fields.
> >      -- DMA alloc and free API signature change in lpass-apq8016.c, lpass-ipq806x.c
> >      -- Keeping API "irqreturn_t lpass_platform_hdmiif_irq" under ifdef macro
> > Changes Since v4:
> >      -- Updated with single compatible node for both I2S and HDMI.
> > Changes Since v3:
> >      -- Removed id in lpass variant structure and used snd_soc_dai_driver id.
> > Changes Since v2:
> >      -- Audio buffer size(i.e. LPASS_PLATFORM_BUFFER_SIZE) in lpass-platform.c increased.
> > Changes Since v1:
> >      -- Commit messages are updated
> >      -- Addressed Rob Herring review comments
> > 
> > V Sujith Kumar Reddy (7):
> >    ASoC: Add sc7180-lpass binding header hdmi define
> >    ASoC: dt-bindings: Add dt binding for lpass hdmi
> >    Asoc:qcom:lpass-cpu:Update dts property read API
> >    Asoc: qcom: lpass:Update lpaif_dmactl members order
> >    ASoC: qcom: Add support for lpass hdmi driver
> >    Asoc: qcom: lpass-platform : Increase buffer size
> >    ASoC: qcom: sc7180: Add support for audio over DP
> > 
> >   .../devicetree/bindings/sound/qcom,lpass-cpu.yaml  |  74 ++--
> >   include/dt-bindings/sound/sc7180-lpass.h           |   1 +
> >   sound/soc/qcom/Kconfig                             |   5 +
> >   sound/soc/qcom/Makefile                            |   2 +
> >   sound/soc/qcom/lpass-apq8016.c                     |   4 +-
> >   sound/soc/qcom/lpass-cpu.c                         | 249 ++++++++++++-
> >   sound/soc/qcom/lpass-hdmi.c                        | 258 ++++++++++++++
> >   sound/soc/qcom/lpass-hdmi.h                        | 102 ++++++
> >   sound/soc/qcom/lpass-ipq806x.c                     |   4 +-
> >   sound/soc/qcom/lpass-lpaif-reg.h                   |  49 ++-
> >   sound/soc/qcom/lpass-platform.c                    | 395 +++++++++++++++++----
> >   sound/soc/qcom/lpass-sc7180.c                      | 116 +++++-
> >   sound/soc/qcom/lpass.h                             | 124 ++++++-
> >   13 files changed, 1240 insertions(+), 143 deletions(-)
> >   create mode 100644 sound/soc/qcom/lpass-hdmi.c
> >   create mode 100644 sound/soc/qcom/lpass-hdmi.h
> > 
> 
> Tested this series on DragonBoard 410c
> 
> Tested-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
> Reviewed-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>

I spent quite some time today trying to track down another regression
for MSM8916/DragonBoard 410c audio in 5.10 and identified this patch
series as the cause. So I'm very surprised that you successfully tested
this on DB410c.

Attempting to play HDMI audio results in:

  ADV7533: lpass_platform_pcmops_hw_params: invalid  interface: 3
  ADV7533: lpass_platform_pcmops_trigger: invalid 3 interface
  apq8016-lpass-cpu 7708000.audio-controller: ASoC: error at soc_component_trigger on 7708000.audio-controller: -22

Attempting to record analog audio results in:

  Unable to handle kernel NULL pointer dereference at virtual address 00000000000001e4
  Internal error: Oops: 96000004 [#1] PREEMPT SMP
  CPU: 1 PID: 1568 Comm: arecord Not tainted 5.11.0-rc3 #20
  Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
  pc : regmap_write+0x14/0x80
  lr : lpass_platform_pcmops_open+0xd8/0x210 [snd_soc_lpass_platform]
  Call trace:
   regmap_write+0x14/0x80
   lpass_platform_pcmops_open+0xd8/0x210 [snd_soc_lpass_platform]
   snd_soc_component_open+0x2c/0x94
   ...

Looking at the changes in "ASoC: qcom: Add support for lpass hdmi driver"
there is a quite obvious mistake there. lpass.h now contains

#include <dt-bindings/sound/sc7180-lpass.h>

and then the SC7810 DAI IDs are hardcoded all over lpass-cpu.c and
lpass-platform.c. But apq8016 and ipq806x have completely different
DAI IDs so now MI2S_QUATERNARY (HDMI) is invalid and
MI2S_TERTIARY (= LPASS_DP_RX in sc7180-lpass.h) is treated as HDMI port.

Effectively LPASS is broken on all platforms except SC7810.

I have a patch prepared to fix this (will send it tomorrow),
but I wonder how you have tested this successfully on DB410c. :)

Stephan