Re: [PATCH v1] ACPI/IORT: Workaround for IORT ID count "minus one" issue

John Garry
2020-01-14T09:47:11Z

On 14/01/2020 07:19, Hanjun Guo wrote:
> On 2020/1/13 17:34, John Garry wrote:
>> On 30/12/2019 12:27, Guohanjun (Hanjun Guo) wrote:
>>> +};
>>> +
>>> +static bool apply_id_count_workaround;
>>> +
>>> +static struct iort_workaround_oem_info wa_info[] __initdata = {
>>> +    {
>>> +        .oem_id        = "HISI  ",
>>> +        .oem_table_id    = "HIP07   ",
>>> +        .oem_revision    = 0,
>>> +    }, {
>>> +        .oem_id        = "HISI  ",
>>> +        .oem_table_id    = "HIP08   ",
>>> +        .oem_revision    = 0,
>>> +    }
>>> +};
>>
>> Am I right in saying that any future BIOS for these chipsets will have to continue to have buggy firmware? If so, it's unfortunate.
>
> For better compatibility, I would say yes :(
>
> For example, if you fix that in the firmware, and update
> the IORT revision number, then it will run pretty good
> on new version of the kernel, but not on old version of
> kernel without the backporting of this patch.

ok, so that seems to be a trade off then. Having to backport introduces
a risk.

So then it might be good to add a comment to ID count members in
open-source edk2-platforms hip07 and hip08 IORTs to mention it is buggy,
so not to be copied as a reference.

Cheers,
John