Re: [PATCH 3/3] hw/riscv/virt-acpi-build.c: Update the HID of RISC-V UART

[Sunil V L]

Hi Igor,
On Wed, Jun 05, 2024 at 04:48:14PM +0200, Igor Mammedov wrote:
> On Tue, 28 May 2024 13:01:03 +0530
> Sunil V L <sunilvl@ventanamicro.com> wrote:
> 
> > RISC-V is going to use new HID RSCV0003 for generi UART. So, update the
> > HID.
> 
> where does it come from?
> 
> > 
> > Signed-off-by: Sunil V L <sunilvl@ventanamicro.com>
> > ---
> >  hw/riscv/virt-acpi-build.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> > 
> > diff --git a/hw/riscv/virt-acpi-build.c b/hw/riscv/virt-acpi-build.c
> > index 47ec78e432..7f80368415 100644
> > --- a/hw/riscv/virt-acpi-build.c
> > +++ b/hw/riscv/virt-acpi-build.c
> > @@ -192,7 +192,7 @@ acpi_dsdt_add_uart(Aml *scope, const MemMapEntry 
> > *uart_memmap,
> >                      uint32_t uart_irq)
> >  {
> >      Aml *dev = aml_device("COM0");
> > -    aml_append(dev, aml_name_decl("_HID", aml_string("PNP0501")));
> > +    aml_append(dev, aml_name_decl("_HID", aml_string("RSCV0003")));
> 
> the only place I've found (that could serve as justification)
>   https://github.com/riscv-non-isa/riscv-brs/blame/main/acpi.adoc
> 
> which mentions _CID and not _HID as it is in this patch
> 
Right, this is the requirement.

Yes, _CID says device is compatible. But different vendors may have
different _HID. For qemu, _CID value is used as _HID since it is not
vendor specific. This is something similar to how ARMH0011 is used (qemu
vs RPi) in ARM world.

I am checking with Andrei to see if we can relax to make it either _HID
or _CID.

Thanks,
Sunil