Re: [PATCH v13] PCI: Add device-specific reset for Qualcomm devices

[Jose Ignacio Tornos Martinez <jtornosm@redhat.com>]

Hi Bjorn,

Thanks for the review.

> I guess you are saying that some kind of reset *does* work
> fine in normal, clean VM termination?  If reset works fine
> for normal VM termination but not for VM crash, do we have
> any idea why they are different?
It depends on the device:

- For the modems (SDX62/SDX65), without a proper reset
  capability, these devices never successfully initialize
  even on first VM assignment.

- For the WLAN devices (WCN6855/WCN7850), the reset fails
  in both cases, but on clean VM shutdown the guest driver's
  .shutdown/.remove callbacks properly deinitialize the device
  (stop DMA, disable interrupts, etc.), so it ends up in a
  known-good state even without a successful reset. On unclean
  termination (crash, force-off), the guest driver callbacks
  never run, the device stays in an undefined state, and
  without a working reset it cannot be reused.

I will try to clarify this better in the commit messages for v14.

> Since these basically copy code from other drivers, is there
> an opportunity to remove it from those drivers and use this
> instead?
Yes, that could be a follow-up after this lands.

> This looks like two patches squashed together.  If there's
> any other reason to touch this patch, I would split them
> apart.
Ok, I will split the WLAN and modem resets into separate
patches for v14.

Thanks

Best regards
Jose Ignacio