[PATCH 1/2] drm/nouveau/bar/gf100: fix hang when calling ->fini() before ->init()

[Ben Skeggs]

On Wed, Dec 6, 2017 at 12:30 AM, Jon Hunter <jonathanh at nvidia.com> wrote:

>
> On 04/12/17 18:37, Guillaume Tucker wrote:
> > If the firmware fails to load then ->fini() will be called before the
> > device has been initialised, causing the kernel to hang while trying
> > to write to a register.  Add a test in ->fini() to avoid this issue.
> >
> > This fixes a kernel hang on tegra124.
> >
> > Fixes: b17de35a2ebbe ("drm/nouveau/bar: implement bar1 teardown")
> > Signed-off-by: Guillaume Tucker <guillaume.tucker at collabora.com>
> > CC: Ben Skeggs <bskeggs at redhat.com>
> > ---
> >  drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c | 7 +++++--
> >  1 file changed, 5 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c
> b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c
> > index a3ba7f50198b..95e2aba64aad 100644
> > --- a/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c
> > +++ b/drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c
> > @@ -43,9 +43,12 @@ gf100_bar_bar1_wait(struct nvkm_bar *base)
> >  }
> >
> >  void
> > -gf100_bar_bar1_fini(struct nvkm_bar *bar)
> > +gf100_bar_bar1_fini(struct nvkm_bar *base)
> >  {
> > -     nvkm_mask(bar->subdev.device, 0x001704, 0x80000000, 0x00000000);
> > +     struct nvkm_device *device = base->subdev.device;
> > +
> > +     if (base->subdev.oneinit)
> > +             nvkm_mask(device, 0x001704, 0x80000000, 0x00000000);
> >  }
> >
> >  void
>
> I have tested this and it works for me. Thanks for fixing this! Would be
> good to get Ben's ACK, but you can have my ...
>
I'd love to get a good explanation as to why it hangs without this change,
as, on the surface, it's not immediately obvious as to why it's hanging.

Thanks,
Ben.


>
> Tested-by: Jon Hunter <jonathanh at nvidia.com>
>
> Cheers
> Jon
>
> --
> nvpublic
>
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