[PATCH v1 07/43] dm: acpi: Add support for the NHLT table

[Bin Meng]

Hi Simon,

On Mon, Jul 13, 2020 at 3:37 AM Simon Glass <sjg at chromium.org> wrote:
>
> Hi Bin,
>
> On Tue, 7 Jul 2020 at 21:25, Simon Glass <sjg at chromium.org> wrote:
> >
> > Hi Bin,
> >
> > On Mon, 6 Jul 2020 at 18:22, Bin Meng <bmeng.cn at gmail.com> wrote:
> > >
> > > Hi Simon,
> > >
> > > On Tue, Jul 7, 2020 at 3:22 AM Simon Glass <sjg at chromium.org> wrote:
> > > >
> > > > Hi Bin,
> > > >
> > > > On Thu, 2 Jul 2020 at 22:33, Bin Meng <bmeng.cn at gmail.com> wrote:
> > > > >
> > > > > Hi Simon,
> > > > >
> > > > > On Fri, Jul 3, 2020 at 11:50 AM Simon Glass <sjg at chromium.org> wrote:
> > > > > >
> > > > > > Hi Bin,
> > > > > >
> > > > > > On Thu, 2 Jul 2020 at 18:54, Bin Meng <bmeng.cn at gmail.com> wrote:
> > > > > > >
> > > > > > > Hi Simon,
> > > > > > >
> > > > > > > On Fri, Jul 3, 2020 at 8:46 AM Simon Glass <sjg at chromium.org> wrote:
> > > > > > > >
> > > > > > > > Hi Bin,
> > > > > > > >
> > > > > > > > On Mon, 29 Jun 2020 at 20:49, Bin Meng <bmeng.cn at gmail.com> wrote:
> > > > > > > > >
> > > > > > > > > Hi Simon,
> > > > > > > > >
> > > > > > > > > On Mon, Jun 15, 2020 at 11:57 AM Simon Glass <sjg at chromium.org> wrote:
> > > > > > > > > >
> > > > > > > > > > The Intel Non-High-Definition-Audio Link Table (NHLT) table describes the
> > > > > > > > > > audio codecs and connections in a system. Various devices can contribute
> > > > > > > > > > information to produce the table.
> > > > > > > > > >
> > > > > > > > > > Add core support for this, based on a structure which is built up through
> > > > > > > > > > calls to the driver.
> > > > > > > > > >
> > > > > > > > > > Signed-off-by: Simon Glass <sjg at chromium.org>
> > > > > > > > > > ---
> > > > > > > > > >
> > > > > > > > > >  drivers/core/acpi.c | 15 +++++++++++++++
> > > > > > > > > >  include/dm/acpi.h   | 26 ++++++++++++++++++++++++++
> > > > > > > > > >  2 files changed, 41 insertions(+)
> > > > > > > > > >
> > > > > > > > > > diff --git a/drivers/core/acpi.c b/drivers/core/acpi.c
> > > > > > > > > > index ea304a3067..a5053fec6f 100644
> > > > > > > > > > --- a/drivers/core/acpi.c
> > > > > > > > > > +++ b/drivers/core/acpi.c
> > > > > > > > > > @@ -31,6 +31,7 @@ enum method_t {
> > > > > > > > > >         METHOD_WRITE_TABLES,
> > > > > > > > > >         METHOD_FILL_SSDT,
> > > > > > > > > >         METHOD_INJECT_DSDT,
> > > > > > > > > > +       METHOD_SETUP_NHLT,
> > > > > > > > >
> > > > > > > > > Do we really need to promote this to be an ACPI core method? Can we
> > > > > > > > > reuse the SSDT/DSDT one?
> > > > > > > >
> > > > > > > > I don't think so. Those two are for a particular purpose. In fact NHLT
> > > > > > > > is generated while doing SSDT I think. The idea is that drivers that
> > > > > > > > want to contribute to NHLT can do so. But we cannot use the SSDT
> > > > > > > > mechanism since each driver contributes only a part of the info, and
> > > > > > > > we need something else to bring it all together.
> > > > > > >
> > > > > > > Will there be only one device that sets up the NHLT info?
> > > > > >
> > > > > > WIth coral it is two devices. I'm not sure of the maximum, but I
> > > > > > suppose it depends on the audio codecs present.
> > > > >
> > > > > Could we make this method to be provided by the codec device, instead
> > > > > of a generic ACPI core method?
> > > >
> > > > The codec device does implement this. See the drivers where they
> > > > actually implement the NHLT method.
> > > >
> > > > This is definitely an ACPI-specific thing, so I think we need core
> > > > support for iterating through drivers that want to provide this info.
> > >
> > > My concern is that this is not generic enough to promote this to ACPI core.
> > >
> > > I wanted to have something like this:
> > >
> > > Create a codec uclass driver, and in the code uclass driver, create an
> > > op that is used to set up the NHLT infor if ACPI_GEN is on.
> >
> > We already have UCLASS_SOUND so could add it to sound_ops. But that
> > seems weird to me since this is not an operation to play a sound. We
> > do this with GIPOs and IRQs but in that case the operation returns
> > some data. Here we are asking the driver to add some data to a table.
> > I'm just not sure it makes sense.
> >
> > What do you think?
>
> Let me know what you think about this as I'd like to finish this series.

I haven't looked into the details of NHLT but I trust your
consideration so let's leave this as it is.

Regards,
Bin