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

[Andy Shevchenko]

On Mon, 2018-06-18 at 21:03 +0800, Bin Meng wrote:
> On Mon, Jun 18, 2018 at 5:22 PM, Andy Shevchenko
> <andriy.shevchenko at linux.intel.com> wrote:
> > 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/comm
> > > > it/?
> > > > 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.
> > 
> 
> I did not find the discussion. Do we need revert the changes in U-
> Boot?

https://patchwork.kernel.org/patch/10098529/

It seems it has been dropped b/c v2 were sent and actually v3 was
anticipated, but never appear.

Also I didn't notice any blessing from hpa about protocol extension.

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