Hi Kieran,
On Tue, Jul 9, 2019 at 12:07 PM Kieran Bingham
<kieran.bingham+renesas@xxxxxxxxxxxxxxxx> wrote:
> On 09/07/2019 10:59, Geert Uytterhoeven wrote:
> > When support for the IPMMU is not enabled, the FDP driver may be
> > probe-deferred multiple times, causing several messages to be printed
> > like:
> >
> > rcar_fdp1 fe940000.fdp1: FCP not found (-517)
> > rcar_fdp1 fe944000.fdp1: FCP not found (-517)
> >
> > Fix this by reducing the message level to debug level, as is done in the
> > VSP1 driver.
>
> Does the lack of IPMMU prevent the FDP1 being loaded entirely?
No it doesn't.
If CONFIG_IPMMU_VMSA=n,
rcar_fdp1 fe940000.fdp1: FCP not found (-517)
rcar_fdp1 fe944000.fdp1: FCP not found (-517)
rcar_fdp1 fe940000.fdp1: FCP not found (-517)
rcar_fdp1 fe944000.fdp1: FCP not found (-517)
rcar_fdp1 fe940000.fdp1: FCP not found (-517)
rcar_fdp1 fe944000.fdp1: FCP not found (-517)
rcar_fdp1 fe940000.fdp1: Device registered as /dev/video8
rcar_fdp1 fe944000.fdp1: Device registered as /dev/video9
So the driver succeeds, eventually.
If CONFIG_IPMMU_VMSA=y, it succeeds sooner:
rcar_fdp1 fe940000.fdp1: Device registered as /dev/video0
rcar_fdp1 fe944000.fdp1: Device registered as /dev/video1
Always be prepared to handle -EPROBE_DEFER.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
