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

[Andy Shevchenko]

On Thu, Sep 13, 2018 at 8:53 AM Jian-Hong Pan <jian-hong@xxxxxxxxxxxx> wrote:
>
> 2018-09-12 16:19 GMT+08:00 Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx>:
> > 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.

Have you seen this thread:
https://patchwork.ozlabs.org/cover/968924/

and this one:
https://patchwork.kernel.org/patch/10583229/

?

> >
> >
> > Hopefully Jian-Hong can cook up a quirk table for the issue.
>
> Module r8169 gets nothing in the PCI BAR after system resumes which
> makes MSI-X fail on some ASUS laptops equipped with RTL8106e chip.
> https://www.spinics.net/lists/linux-pci/msg75598.html
>
> Actually, I am waiting for the patch "PCI: Reprogram bridge prefetch
> registers on resume" being merged.
> https://marc.info/?l=linux-pm&m=153680987814299&w=2
>
> It resolves the drivers which get nothing in PCI BAR after system resumes.
>
> After that, I can remove the falling back code of RTL8106e.
>
> Heiner, any comment?
>
> Regards,
> Jian-Hong Pan
>
> >>
> >>> 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
> >
> >
> >



-- 
With Best Regards,
Andy Shevchenko