Re: [Xen-devel] [RFC PATCH 01/12] libacpi: new DSDT ACPI table for Q35

[Alexey G <x1917x@xxxxxxxxx>]

On Mon, 19 Mar 2018 12:43:05 +0000
Roger Pau Monné <roger.pau@xxxxxxxxxx> wrote:

>On Tue, Mar 13, 2018 at 04:33:46AM +1000, Alexey Gerasimenko wrote:
>> This patch adds the DSDT table for Q35 (new
>> tools/libacpi/dsdt_q35.asl file). There are not many differences
>> with dsdt.asl (for i440) at the moment, namely:
>> 
>> - BDF location of LPC Controller
>> - Minor changes related to FDC detection
>> - Addition of _OSC method to inform OSPM about PCIe features
>> supported
>> 
>> As we are still using 4 PCI router links and their corresponding
>> device/register addresses are same (offset 0x60), no need to change
>> PCI routing descriptions.
>> 
>> Also, ACPI hotplug is still used to control passed through device hot
>> (un)plug (as it was for i440).
>> 
>> Signed-off-by: Alexey Gerasimenko <x1917x@xxxxxxxxx>
>> ---
>>  tools/libacpi/dsdt_q35.asl | 551
>> +++++++++++++++++++++++++++++++++++++++++++++  
>
>So this is basically a modified dupe of the current dsdt.asl? AFAICT
>there are a bunch of common bits, which ideally we want to have
>defined in a single place.
>
>Can't you factor out the common parts of the dsdt.asl into smaller
>parts an include them for both dsdt.asl and dsdt_q35.asl?
>
>I would first have a patch that extract the common parts of the
>dsdt into file(s), and then a second patch which creates a
>dsdt_q35.asl based on those common bits plus the specific q35 code.

Yes, it's a good thing that many registers have same addresses on
i440 and Q35. Some encountered common things were unexpected though --
AFAIR _S5 SLP_TYP value do not correspond to the ICH9 datasheet,
a different value used instead to trigger ACPI Soft-Off emulation.

Regarding dsdt.asl/dsdt_q35.asl -- OK, I'll split these files into
common/specific parts.

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