Subject: Re: [PATCH v2 2/4] gpu/radeon: Move 64-bit MSI quirk from arch to driver

From: Benjamin Herrenschmidt <[email-masked]>
Date: Fri, 03 Oct 2014 08:23:13 +1000

On Thu, 2014-10-02 at 15:44 -0600, Bjorn Helgaas wrote:
> On Thu, Oct 2, 2014 at 3:02 PM, Benjamin Herrenschmidt
> <[email-masked]> wrote:
> > On Thu, 2014-10-02 at 09:34 -0600, Bjorn Helgaas wrote:
> >> On Thu, Oct 02, 2014 at 10:34:22AM +1000, Benjamin Herrenschmidt wrote:
> >> >
> >> > A number of radeon cards have a HW limitation causing them to be
> >> > unable to generate the full 64-bit of address bits for MSIs. This
> >> > breaks MSIs on some platforms such as POWER machines.
> >> >
> >> > We used to have a powerpc specific quirk to address that on a
> >> > single card, but this doesn't scale very well, this is better
> >> > put under control of the drivers who know precisely what a given
> >> > HW revision can do.
> >> >
> >> > This moves the setting of the quirk flag to the radeon driver
> >> >
> >> > Signed-off-by: Benjamin Herrenschmidt <[email-masked]>
> >> > ---
> >> >
> >> > v2: This is just adjusted to the new flag name
> >>
> >> I'm sorta confused because I got two "v2 2/4" emails a minute or so apart.
> >> I assume they're the same.
> >
> > Yes, evo blew up while sending the series the first time around :(
> 
> No problem.  My real question is below, but you probably missed it
> because of my email gripe :)

Heh ok :-)

> >> >  arch/powerpc/kernel/pci_64.c            |  1 -
> >> >  drivers/gpu/drm/radeon/radeon_irq_kms.c | 10 ++++++++++
> >> >  2 files changed, 10 insertions(+), 1 deletion(-)
> >> >
> >> > diff --git a/arch/powerpc/kernel/pci_64.c b/arch/powerpc/kernel/pci_64.c
> >> > index d41a831..5330f6d 100644
> >> > --- a/arch/powerpc/kernel/pci_64.c
> >> > +++ b/arch/powerpc/kernel/pci_64.c
> >> > @@ -271,5 +271,4 @@ static void quirk_radeon_32bit_msi(struct pci_dev *dev)
> >> >  {
> >> >     dev->no_64bit_msi = true;
> >> >  }
> >> > -DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0x68f2, quirk_radeon_32bit_msi);
> >> >  DECLARE_PCI_FIXUP_FINAL(PCI_VENDOR_ID_ATI, 0xaa68, quirk_radeon_32bit_msi);
> >>
> >> Why do we keep the 0xaa68 quirk?  Shouldn't that be made generic, too?

aa68 is the audio part, it's removed by the audio driver patch.

But I can break things down into smaller bits as you suggested. I'll try
to get that sorted later today.

Cheers,
Ben.

> >> > diff --git a/drivers/gpu/drm/radeon/radeon_irq_kms.c b/drivers/gpu/drm/radeon/radeon_irq_kms.c
> >> > index 16807af..e760671 100644
> >> > --- a/drivers/gpu/drm/radeon/radeon_irq_kms.c
> >> > +++ b/drivers/gpu/drm/radeon/radeon_irq_kms.c
> >> > @@ -202,6 +202,16 @@ static bool radeon_msi_ok(struct radeon_device *rdev)
> >> >     if (rdev->flags & RADEON_IS_AGP)
> >> >             return false;
> >> >
> >> > +   /*
> >> > +    * Older chips have a HW limitation, they can only generate 40 bits
> >> > +    * of address for "64-bit" MSIs which breaks on some platforms, notably
> >> > +    * IBM POWER servers, so we limit them
> >> > +    */
> >> > +   if (rdev->family < CHIP_BONAIRE) {
> >> > +           dev_info(rdev->dev, "radeon: MSI limited to 32-bit\n");
> >> > +           rdev->pdev->no_64bit_msi = true;
> >> > +   }
> >> > +
> >> >     /* force MSI on */
> >> >     if (radeon_msi == 1)
> >> >             return true;
> >> >
> >> >
> >> >
> >
> >