Re: [PATCH net] igc: Disable PCIe L1.2 substate on I225-LMvP and I226-LMvP devices

["Ruinskiy, Dima" <dima.ruinskiy@intel.com>]

On 29/09/2026 14:41, netdev-bot+sashiko@kernel.org wrote:
> Thank you for your contribution! Sashiko AI review found 3 potential
> issue(s) to consider.
> 
> Critical: 0 · High: 1 (1) · Medium: 1 · Low: 1
> 
> If you believe none of the issues are legitimate, please reply to each
> issue of Medium severity or higher and explain why the AI is wrong.
> If any of them are legitimate and you plan to respin, please let patchwork
> know by including "pw-bot: cr" as a separate line at the end of your reply
> (one such reply per series is enough).
> 
> - [High] The widened condition in `__igc_resume()` (igc_main.c:7562-7563)
>    makes I225-LMvP and I226-LMvP call the non-locked…
> - [Medium] Adding `IGC_DEV_ID_I226_LMVP` to `igc_is_device_id_i226()`
>    (drivers/net/ethernet/intel/igc/igc_base.c:450) changes more than the…
> - [Low] In `igc_probe()`, `__igc_resume()` and `igc_io_slot_reset()`, the
>    return value of…
> 
> Pre-existing issues:
> - [High] This problem wasn't introduced by this patch, but the patch now
>    exposes I226-LMvP to it.
> 
> --
> 
> igc: Disable PCIe L1.2 substate on I225-LMvP and I226-LMvP devices
> 
> This commit adds IGC_DEV_ID_I226_LMVP to igc_is_device_id_i226(). It also
> extends the ASPM L1.2 disable in probe, resume and PCI error recovery to
> IGC_DEV_ID_I225_LMVP. The motivation is BadDLLP errors, link timeouts and
> shutdown hangs seen when I225-LMvP negotiates L1.2 behind Thunderbolt/USB4
> docks.
> 
> Link: https://lore.kernel.org/lkml/eb5a9805-3e53-ec22-696e-21c6b8cf0bfc@molgen.mpg.de/T/

I think this patch might better be split into several patches.

1. Adding the missing IGC_DEV_ID_I226_LMVP to igc_is_device_id_i226(). 
This was probably an accidental omission.

2. Addressing the locked vs. non-locked call to pci_disable_link_state 
(the possible deadlock noted by Sashiko) - this should be looked into a 
bit more, I don't know off the top of my head what race is / isn't possible.

3. The actual problem with L1.2 substate this patch aims to solve. I 
checked with the HW team and there are two conclusions - (a) it is 
strange that L1.2 is enabled somehow for I225_LMVP - this is not 
expected. (b) generally it is probably best and simplest to remove any 
device ID checks and simply disable L1.2 across the board in this 
driver. Unless there are downsides to calling the API when it is already 
disabled (I don't expect there are).

--Dima