Re: Regression caused by commit 7bb05b85bc2d ("r8169: don't use MSI-X on RTL8106e")

[Kai-Heng Feng]

at 14:32, Thomas Gleixner <tglx@xxxxxxxxxxxxx> wrote:

> On Wed, 12 Sep 2018, Kai-Heng Feng wrote:
>
> > There's a Dell machine with RTL8106e stops to work after S3 since the
> > commit introduced. So I am wondering if it's possible to revert the
> > commit and use DMI/subsystem id based quirk table?
>
> Probably.

Hopefully Jian-Hong can cook up a quirk table for the issue.

> > It's because of commit bc976233a872 ("genirq/msi, x86/vector: Prevent
> > reservation mode for non maskable MSI") cleared the reservation mode,  
> > and I
> > can see this after S3:
> >
> > [   94.872838] do_IRQ: 3.33 No irq handler for vector
>
> It's not because of that commit, really. There is a interrupt sent after
> resume to the wrong vector for whatever reason. The MSI vector cannot be
> masked it seems in the device, but the driver should quiescen the device to
> a point where it does not send interrupts.

Understood.

> > If the device uses MSI-X instead of MSI, the issue doesn't happen  
> > because of
> > reservation mode.
>
> Reservation mode has absolutely nothing to do with that. What prevents the
> issue is the fact that MSI-X can be masked by the IRQ core.

So in this case I think keep the device using MSI-X is a better route, it's  
MSI-X capable anyway.

> > Is it something should be handled by x86 BIOS? Because I don't see this  
> > issue
> > when I use Suspend-to-Idle, which doesn't use BIOS to do suspend.
>
> Suspend to idle works completely different and I don't see the BIOS at
> fault here. it's more an issue of MSI not being maskable on that device,
> which can't be fixed in BIOS or it's some half quiescened state which is
> used when suspending and that's a pure driver issue.

Understood.
Thanks for all the info!

Kai-Heng

> Thanks,
>
> 	tglx