Re: [Qemu-devel] [PATCH v4 27/33] nvdimm acpi: save arg3 for NVDIMM device _DSM method

[Dan Williams]

On Mon, Oct 19, 2015 at 2:19 PM, Michael S. Tsirkin <address@hidden> wrote:
> On Mon, Oct 19, 2015 at 10:29:50AM -0700, Dan Williams wrote:
>> On Mon, Oct 19, 2015 at 12:09 AM, Michael S. Tsirkin <address@hidden> wrote:
>> > On Mon, Oct 19, 2015 at 12:04:48PM +0800, Xiao Guangrong wrote:
>> > I mean don't use ASL to comment C. It's not more readable.
>> > Describe why the code is the way it is. Use variables by preference,
>> > C does not have weird limitations like ASL so you don't need to call
>> > your variables "arg3". What does it hold?
>> >
>>
>> What it holds is function number specific.  It's similar to
>> SYSCALL_DEFINEx where the ASL code is there to marshal arguments from
>> the OS through ACPI to a BIOS routine.  See the definition of the
>> example _DSM functions here and the usages of "Arg3":
>> http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf
>
> So it seems to say "3.1.1.1.1 Input (Arg3)".
> Is that right? So
>
> Aml *input = aml_arg(3); /* Input (Arg3) */
> or even
> Aml *input_arg3 =  aml_arg(3); /* Input (Arg3) */
>
> My point is we are not writing ASL. There is no reason
> to use cryptic names.
>

Ah, ok, sounds good to me.  ASL is already hard to read and we
shouldn't be using it as code commentary.