> -----Original Message-----
> From: Sunil V L <sunilvl@ventanamicro.com>
> Sent: Monday, August 26, 2024 3:14 PM
> To: JeeHeng Sia <jeeheng.sia@starfivetech.com>
> Cc: qemu-arm@nongnu.org; qemu-devel@nongnu.org; qemu-riscv@nongnu.org; mst@redhat.com; imammedo@redhat.com;
> anisinha@redhat.com; peter.maydell@linaro.org; shannon.zhaosl@gmail.com; palmer@dabbelt.com; alistair.francis@wdc.com;
> bin.meng@windriver.com; liwei1518@gmail.com; dbarboza@ventanamicro.com; zhiwei_liu@linux.alibaba.com
> Subject: Re: [PATCH RESEND v4 0/3] Upgrade ACPI SPCR table to support SPCR table revision 4 format
> 
> Hi Jee Heng,
> 
> On Mon, Aug 26, 2024 at 07:04:11AM +0000, JeeHeng Sia wrote:
> >
> >
> > > -----Original Message-----
> > > From: Sunil V L <sunilvl@ventanamicro.com>
> > > Sent: Friday, August 23, 2024 10:29 PM
> > > To: JeeHeng Sia <jeeheng.sia@starfivetech.com>
> > > Cc: qemu-arm@nongnu.org; qemu-devel@nongnu.org; qemu-riscv@nongnu.org; mst@redhat.com; imammedo@redhat.com;
> > > anisinha@redhat.com; peter.maydell@linaro.org; shannon.zhaosl@gmail.com; palmer@dabbelt.com; alistair.francis@wdc.com;
> > > bin.meng@windriver.com; liwei1518@gmail.com; dbarboza@ventanamicro.com; zhiwei_liu@linux.alibaba.com
> > > Subject: Re: [PATCH RESEND v4 0/3] Upgrade ACPI SPCR table to support SPCR table revision 4 format
> > >
> > > Hi Jee Heng,
> > > On Fri, Aug 23, 2024 at 04:31:39AM -0700, Sia Jee Heng wrote:
> > > > Update the SPCR table to accommodate the SPCR Table revision 4 [1].
> > > > The SPCR table has been modified to adhere to the revision 4 format [2].
> > > >
> > > > Meanwhile, the virt SPCR golden reference file for RISC-V have been updated to
> > > > accommodate the SPCR Table revision 4.
> > > >
> > > > [1]: https://learn.microsoft.com/en-us/windows-hardware/drivers/serports/serial-port-console-redirection-table
> > > > [2]: https://github.com/acpica/acpica/pull/931
> > > >
> > > Just curious - whether this needs changes in linux side as well? Does
> > > current linux code work fine with version 4 of SPCR table on RISC-V?
> > The current Linux ACPI Table has not yet been updated to support SPCR v4.
> > However, Linux RISC-V will be able to use the information in the QEMU's
> > SPCR table to boot with behaviour similar to ARM.
> > >
> So, it means even if qemu risc-v SPCR is upgraded to version 4,
> current linux continues to work. It may be just able to decode SPCR v2
> fields only until enhanced to understand v4 but but doesn't break
> anything or crash. Is that correct?
Yes, correct.
> 
> Just wanted to confirm qemu changes can get merged without any
> dependency.
> 
> Thanks!
> Sunil