[U-Boot] [PATCH v1 2/2] x86: zImage: Propagate acpi_rsdp_addr to kernel via boot parameters

[Andy Shevchenko]

On Sun, 2018-06-17 at 07:22 +0800, Bin Meng wrote:
> Hi Andy,
> 
> On Fri, Jan 12, 2018 at 9:01 PM, Andy Shevchenko
> <andriy.shevchenko at linux.intel.com> wrote:
> > On Fri, 2018-01-12 at 17:00 +0800, Bin Meng wrote:
> > > Hi Andy,
> > > 
> > > On Thu, Jan 11, 2018 at 1:40 AM, Andy Shevchenko
> > > <andriy.shevchenko at linux.intel.com> wrote:
> > > > New field acpi_rsdp_addr, which has been introduced in boot
> > > > protocol
> > > > v2.14 [1], in boot parameters tells kernel the exact address of
> > > > RDSP
> > > > ACPI table. Knowing it increases robustness of the kernel by
> > > > avoiding
> > > > in some cases traversal through a part of physical memory.
> > > > It will slightly reduce boot time by the same reason.
> > > > 
> > > > [1] See Linux kernel commit
> > > > 
> > > >   2f74cbf947f4 ("x86/boot: Add the ACPI RSDP address to struct
> > > > setup_header::acpi_rdsp_addr")
> > > 
> > > I don't see this commit id in my linux tree. Is this in some
> > > custodian's tree?
> > 
> > https://git.kernel.org/pub/scm/linux/kernel/git/tip/tip.git/commit/?
> > id=2
> > f74cbf947f45fa082dda8eac1a1f1299a372f49
> > 
> 
> I checked Linux kernel tree, seems the patch of adding acpi_rdsp_addr
> to setup_header was never accepted. Can you please double check, to
> see whether we still need this in U-Boot?
> 
> I built a v4.17 kernel, and the boot protocol is still 2.13.

Indeed. There were a discussion to not apply it for now.

-- 
Andy Shevchenko <andriy.shevchenko at linux.intel.com>
Intel Finland Oy