Re: [PATCH v2 0/5] tpm_tis: fix interrupts (again)

[Jerry Snitselaar <jsnitsel@redhat.com>]

Hans de Goede @ 2020-10-14 09:04 MST:

> Hi,
>
> On 10/14/20 5:23 PM, James Bottomley wrote:
>> On Wed, 2020-10-14 at 17:03 +0200, Hans de Goede wrote:
>>> On 10/13/20 6:05 PM, Jerry Snitselaar wrote:
>>>> James Bottomley @ 2020-10-13 08:24 MST:
>>>>> On Tue, 2020-10-13 at 08:15 -0700, Jerry Snitselaar wrote:
>>>>>> Jarkko Sakkinen @ 2020-10-12 18:17 MST:
>> [...]
>>>>>>>    Jerry, once you have some bandwidth (no rush, does not land
>>>>>>> before rc2), it would be great that if you could try this.
>>>>>>> I'm emphasizing this just because of the intersection. I
>>>>>>> think it would also make senset to get tested-by from Nayna.
>>>>>>
>>>>>> I will run some tests on some other systems I have access to.
>>>>>> As noted in the other email I did a quick test with a t490s
>>>>>> with an older bios that exhibits the problem originally
>>>>>> reported when Stefan's patch enabled interrupts.
>>>>>
>>>>> Well, it means there's still some other problem.  I was hoping
>>>>> that because the rainbow pass system originally exhibited the
>>>>> same symptoms (interrupt storm) fixing it would also fix the t490
>>>>> and the ineffective EOI bug looked like a great candidate for
>>>>> being the root cause.
>>>>>
>>>>
>>>> Adding Hans to the list.
>>>>
>>>> IIUC in the t490s case the problem lies with the hardware itself.
>>>> Hans, is that correct?
>>>
>>> More or less. AFAIK / have been told by Lenovo it is an issue with
>>> the configuration of the inerrupt-type of the GPIO pin used for the
>>> IRQ, which is a firmware issue which could be fixed by a BIOS update
>>> (the pin is setup as a direct-irq pin for the APIC, so the OS has no
>>> control of the IRQ type since with APIC irqs this is all supposed to
>>> be setup properly before hand).
>>>
>>> But it is a model specific issue, if we denylist IRQ usage on this
>>> Lenovo model (and probably a few others) then we should be able to
>>> restore the IRQ code to normal functionality for all other device
>>> models which declare an IRQ in their resource tables.
>> I can do that with a quirk, but how do I identify the device?  TPM
>> manufacturer and version? or do I have to use something like the ACPI
>> bios version?
>
> I'm not sure if the TPM ids are unique to one model/series of laptops.
>
> So my idea for this was to match on DMI strings, specifically
> use a DMI match on the DMI_SYS_VENDOR and DMI_PRODUCT_VERSION
> strings (normally one would use DMI_PRODUCT_NAME but for Lenovo
> devices the string which you expect to be in DMI_PRODUCT_NAME
> is actually in DMI_PRODUCT_VERSION).
>
> You can easily get the strings for your device by doing:
>
> cat /sys/class/dmi/id/sys_vendor
> cat /sys/class/dmi/id/product_version
>
> Regards,
>
> Hans

Plus use dmi_get_date(DMI_BIOS_DATE,...) to check
if the bios is older than the fixed bios? Has Lenovo
released the fixed bios?