Re: [PATCH 07/15] drm/amdgpu: use PCI_IRQ_MSI_TYPES where appropriate

From: Andy Shevchenko
Date: Tue Jun 02 2020 - 06:00:04 EST


On Tue, Jun 2, 2020 at 12:58 PM Stankiewicz, Piotr
<piotr.stankiewicz@xxxxxxxxx> wrote:
> > -----Original Message-----
> > From: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
> > Sent: Tuesday, June 2, 2020 11:49 AM
> > To: Stankiewicz, Piotr <piotr.stankiewicz@xxxxxxxxx>
> > Cc: Alex Deucher <alexander.deucher@xxxxxxx>; Christian KÃnig
> > <christian.koenig@xxxxxxx>; David Zhou <David1.Zhou@xxxxxxx>; David
> > Airlie <airlied@xxxxxxxx>; Daniel Vetter <daniel@xxxxxxxx>; amd-
> > gfx@xxxxxxxxxxxxxxxxxxxxx; dri-devel <dri-devel@xxxxxxxxxxxxxxxxxxxxx>; Linux
> > Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>
> > Subject: Re: [PATCH 07/15] drm/amdgpu: use PCI_IRQ_MSI_TYPES where
> > appropriate
> > On Tue, Jun 2, 2020 at 12:24 PM Piotr Stankiewicz
> > <piotr.stankiewicz@xxxxxxxxx> wrote:

...

> > > int nvec = pci_msix_vec_count(adev->pdev);
> > > unsigned int flags;
> > >
> > > - if (nvec <= 0) {
> > > + if (nvec > 0)
> > > + flags = PCI_IRQ_MSI_TYPES;
> > > + else
> > > flags = PCI_IRQ_MSI;
> > > - } else {
> > > - flags = PCI_IRQ_MSI | PCI_IRQ_MSIX;
> > > - }
> > > +
> > > /* we only need one vector */
> > > nvec = pci_alloc_irq_vectors(adev->pdev, 1, 1, flags);
> >
> > I'm not sure if you have seen my last comment internally about this patch.
> >
> > I don't understand why we need these pci_msix_vec_count() followed by
> > conditional at all.
> > Perhaps we may simple drop all these and supply flag directly?
> >
> > But OTOH, I don't know the initial motivation, so, the above patch is
> > non-intrusive and keeps original logic.
> >
>
> Sorry, I must have misunderstood or missed that comment. I am happy
> to do a V2 if dropping the conditional is preferable.

Let's wait for AMD people to confirm either.

--
With Best Regards,
Andy Shevchenko