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

[James Bottomley <James.Bottomley@HansenPartnership.com>]

On Wed, 2020-10-14 at 09:34 -0700, Jerry Snitselaar wrote:
> 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?

Yes, get all the DMI before and after information, but ideally also the
TIS before and after information.  That's what you get from the tpm_tis
line in dmesg:

tpm_tis MSFT0101:00: 2.0 TPM (device-id 0xFE, rev-id 2)

What I was hoping is rev-id might change.  However, if the bug is
specific to the Lenovo firmware and not the TPM firmware, that is
unlikely.

James