TPM interrupt patch on LTS

TPM interrupt patch on LTS

[João Paulo Silva Gonçalves]

Hello, 

We are integrating a SPI TPM from Infineon with 6.1/5.15 LTS kernels for an 
embedded platform and it is giving an error message that interrupts are not working. 
There is a correction from [1] already on upstream but the patch that makes 
interrupts work, commit e644b2f498d2 ("tpm, tpm_tis: Enable interrupt test"), was 
not backported to LTS. This seems to be the only patch that was no backported 
from [1]. I read some discussion on lkml about TPM interrupts problems but did 
not get if it is related or the reason for not backporting the patch. 

Do you know the reason this single patch was not backported?  

[1] https://lore.kernel.org/lkml/20221124135538.31020-1-LinoSanfilippo@gmx.de/

Thanks!

Regards,
Joao Paulo Goncalves

Re: TPM interrupt patch on LTS

[Jarkko Sakkinen]

On Tue Dec 26, 2023 at 4:50 PM EET, João Paulo Silva Gonçalves wrote:
> Hello, 
>
> We are integrating a SPI TPM from Infineon with 6.1/5.15 LTS kernels for an 
> embedded platform and it is giving an error message that interrupts are not working. 
> There is a correction from [1] already on upstream but the patch that makes 
> interrupts work, commit e644b2f498d2 ("tpm, tpm_tis: Enable interrupt test"), was 
> not backported to LTS. This seems to be the only patch that was no backported 
> from [1]. I read some discussion on lkml about TPM interrupts problems but did 
> not get if it is related or the reason for not backporting the patch. 
>
> Do you know the reason this single patch was not backported?  
>
> [1] https://lore.kernel.org/lkml/20221124135538.31020-1-LinoSanfilippo@gmx.de/
>
> Thanks!
>
> Regards,
> Joao Paulo Goncalves

You can disable interrupts with "interrupts" kernel command-line
parameter. It's not backported because essentialy it is a feature,
i.e. interrupts have been never working before properly.

BR, Jarkko