[PATCH] vgaarb: Stub vga_set_legacy_decoding()

[PATCH] vgaarb: Stub vga_set_legacy_decoding()

[Alex Williamson]

vga_set_legacy_decoding() is defined in drivers/gpu/vga/vgaarb.c,
which is only compiled with CONFIG_VGA_ARB.  A caller would
therefore get an undefined symbol if the VGA arbiter is not
enabled.

Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
---

I'd like to use this function from vfio-pci to opt-out VGA devices
from arbitration if vfio-pci VGA support is disabled.  This helps to
keep DRI2 enabled on the host if additional GPUs are installed for
VMs and used without VGA support.  I can pull this change in through
my tree if someone wants to provide just an ack.  Thanks!

 include/linux/vgaarb.h |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h
index c37bd4d..8c3b412 100644
--- a/include/linux/vgaarb.h
+++ b/include/linux/vgaarb.h
@@ -65,8 +65,13 @@ struct pci_dev;
  *     out of the arbitration process (and can be safe to take
  *     interrupts at any time.
  */
+#if defined(CONFIG_VGA_ARB)
 extern void vga_set_legacy_decoding(struct pci_dev *pdev,
 				    unsigned int decodes);
+#else
+static inline void vga_set_legacy_decoding(struct pci_dev *pdev,
+					   unsigned int decodes) { };
+#endif
 
 /**
  *     vga_get         - acquire & locks VGA resources

Re: [PATCH] vgaarb: Stub vga_set_legacy_decoding()

[Dave Airlie]

On 25 February 2015 at 02:16, Alex Williamson
<alex.williamson@redhat.com> wrote:
> vga_set_legacy_decoding() is defined in drivers/gpu/vga/vgaarb.c,
> which is only compiled with CONFIG_VGA_ARB.  A caller would
> therefore get an undefined symbol if the VGA arbiter is not
> enabled.

Acked-by: Dave Airlie <airlied@redhat.com>

> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> ---
>
> I'd like to use this function from vfio-pci to opt-out VGA devices
> from arbitration if vfio-pci VGA support is disabled.  This helps to
> keep DRI2 enabled on the host if additional GPUs are installed for
> VMs and used without VGA support.  I can pull this change in through
> my tree if someone wants to provide just an ack.  Thanks!
>
>  include/linux/vgaarb.h |    5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h
> index c37bd4d..8c3b412 100644
> --- a/include/linux/vgaarb.h
> +++ b/include/linux/vgaarb.h
> @@ -65,8 +65,13 @@ struct pci_dev;
>   *     out of the arbitration process (and can be safe to take
>   *     interrupts at any time.
>   */
> +#if defined(CONFIG_VGA_ARB)
>  extern void vga_set_legacy_decoding(struct pci_dev *pdev,
>                                     unsigned int decodes);
> +#else
> +static inline void vga_set_legacy_decoding(struct pci_dev *pdev,
> +                                          unsigned int decodes) { };
> +#endif
>
>  /**
>   *     vga_get         - acquire & locks VGA resources
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@lists.freedesktop.org
> http://lists.freedesktop.org/mailman/listinfo/dri-devel

Re: [PATCH] vgaarb: Stub vga_set_legacy_decoding()

[Alex Williamson]

On Thu, 2015-03-05 at 09:43 +1000, Dave Airlie wrote:
> On 25 February 2015 at 02:16, Alex Williamson
> <alex.williamson@redhat.com> wrote:
> > vga_set_legacy_decoding() is defined in drivers/gpu/vga/vgaarb.c,
> > which is only compiled with CONFIG_VGA_ARB.  A caller would
> > therefore get an undefined symbol if the VGA arbiter is not
> > enabled.
> 
> Acked-by: Dave Airlie <airlied@redhat.com>

Thanks Dave!  I'll route this through my tree with the commit that uses
it.

> > Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
> > ---
> >
> > I'd like to use this function from vfio-pci to opt-out VGA devices
> > from arbitration if vfio-pci VGA support is disabled.  This helps to
> > keep DRI2 enabled on the host if additional GPUs are installed for
> > VMs and used without VGA support.  I can pull this change in through
> > my tree if someone wants to provide just an ack.  Thanks!
> >
> >  include/linux/vgaarb.h |    5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/include/linux/vgaarb.h b/include/linux/vgaarb.h
> > index c37bd4d..8c3b412 100644
> > --- a/include/linux/vgaarb.h
> > +++ b/include/linux/vgaarb.h
> > @@ -65,8 +65,13 @@ struct pci_dev;
> >   *     out of the arbitration process (and can be safe to take
> >   *     interrupts at any time.
> >   */
> > +#if defined(CONFIG_VGA_ARB)
> >  extern void vga_set_legacy_decoding(struct pci_dev *pdev,
> >                                     unsigned int decodes);
> > +#else
> > +static inline void vga_set_legacy_decoding(struct pci_dev *pdev,
> > +                                          unsigned int decodes) { };
> > +#endif
> >
> >  /**
> >   *     vga_get         - acquire & locks VGA resources
> >
> > _______________________________________________
> > dri-devel mailing list
> > dri-devel@lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/dri-devel