| Message ID | 1432102224-15169-1-git-send-email-acourbot@nvidia.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On Wednesday 20 May 2015 15:10:24 Alexandre Courbot wrote: > The lack of IOMMU API support can make nouveau_platform_probe_iommu() > fail to compile because struct iommu_ops is then empty. Fix this by > skipping IOMMU probe in that case - lack of IOMMU on platform devices > is sub-optimal, but is not an error. > > Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> > --- > This is an alternative to https://lkml.org/lkml/2015/5/19/484. Most users > of Nouveau do not care about IOMMU support, so we should not impose that > option on them. > Yes, good idea. Acked-by: Arnd Bergmann <arnd@arndb.de>
On Wed, May 20, 2015 at 03:10:24PM +0900, Alexandre Courbot wrote: > The lack of IOMMU API support can make nouveau_platform_probe_iommu() > fail to compile because struct iommu_ops is then empty. Fix this by > skipping IOMMU probe in that case - lack of IOMMU on platform devices > is sub-optimal, but is not an error. > > Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> > --- > This is an alternative to https://lkml.org/lkml/2015/5/19/484. Most users > of Nouveau do not care about IOMMU support, so we should not impose that > option on them. > > drm/nouveau/nouveau_platform.c | 16 ++++++++++++++++ > 1 file changed, 16 insertions(+) > > diff --git a/drivers/gpu/drm/nouveau/nouveau_platform.c b/drivers/gpu/drm/nouveau/nouveau_platform.c > index 775277f1edb0..dcfbbfaf1739 100644 > --- a/drivers/gpu/drm/nouveau/nouveau_platform.c > +++ b/drivers/gpu/drm/nouveau/nouveau_platform.c > @@ -92,6 +92,8 @@ static int nouveau_platform_power_down(struct nouveau_platform_gpu *gpu) > return 0; > } > > +#if IS_ENABLED(CONFIG_IOMMU_API) > + > static void nouveau_platform_probe_iommu(struct device *dev, > struct nouveau_platform_gpu *gpu) > { > @@ -158,6 +160,20 @@ static void nouveau_platform_remove_iommu(struct device *dev, > } > } > > +#else > + > +static void nouveau_platform_probe_iommu(struct device *dev, > + struct nouveau_platform_gpu *gpu) > +{ > +} > + > +static void nouveau_platform_remove_iommu(struct device *dev, > + struct nouveau_platform_gpu *gpu) > +{ > +} > + > +#endif > + Since these are all static functions, perhaps an "if (IS_ENABLED(...))" would work here? That way you'd get compile coverage of the code in all cases. But perhaps that doesn't work for IOMMU. I have a vague memory of running across something like this before and IOMMU has this quirk of defining struct iommu_ops as empty if IOMMU_API is deselected so you'll probably get compiler errors unless you actually preprocess the code out. Thierry
On Wednesday 20 May 2015 13:32:33 Thierry Reding wrote: > > Since these are all static functions, perhaps an "if (IS_ENABLED(...))" > would work here? That way you'd get compile coverage of the code in all > cases. I had the same thought at first. > But perhaps that doesn't work for IOMMU. I have a vague memory of > running across something like this before and IOMMU has this quirk of > defining struct iommu_ops as empty if IOMMU_API is deselected so you'll > probably get compiler errors unless you actually preprocess the code > out. Exactly. Arnd
On Wed, May 20, 2015 at 9:01 PM, Arnd Bergmann <arnd@arndb.de> wrote: > On Wednesday 20 May 2015 13:32:33 Thierry Reding wrote: >> >> Since these are all static functions, perhaps an "if (IS_ENABLED(...))" >> would work here? That way you'd get compile coverage of the code in all >> cases. > > I had the same thought at first. > >> But perhaps that doesn't work for IOMMU. I have a vague memory of >> running across something like this before and IOMMU has this quirk of >> defining struct iommu_ops as empty if IOMMU_API is deselected so you'll >> probably get compiler errors unless you actually preprocess the code >> out. > > Exactly. That's precisely the issue here, so not covering this code is exactly what we want if !CONFIG_IOMMU.
On Wed, May 20, 2015 at 4:07 PM, Arnd Bergmann <arnd@arndb.de> wrote: > On Wednesday 20 May 2015 15:10:24 Alexandre Courbot wrote: >> The lack of IOMMU API support can make nouveau_platform_probe_iommu() >> fail to compile because struct iommu_ops is then empty. Fix this by >> skipping IOMMU probe in that case - lack of IOMMU on platform devices >> is sub-optimal, but is not an error. >> >> Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> >> --- >> This is an alternative to https://lkml.org/lkml/2015/5/19/484. Most users >> of Nouveau do not care about IOMMU support, so we should not impose that >> option on them. >> > > Yes, good idea. > > Acked-by: Arnd Bergmann <arnd@arndb.de> Thanks. Dave, are you ok with this patch? If so, can you take it?
diff --git a/drivers/gpu/drm/nouveau/nouveau_platform.c b/drivers/gpu/drm/nouveau/nouveau_platform.c index 775277f1edb0..dcfbbfaf1739 100644 --- a/drivers/gpu/drm/nouveau/nouveau_platform.c +++ b/drivers/gpu/drm/nouveau/nouveau_platform.c @@ -92,6 +92,8 @@ static int nouveau_platform_power_down(struct nouveau_platform_gpu *gpu) return 0; } +#if IS_ENABLED(CONFIG_IOMMU_API) + static void nouveau_platform_probe_iommu(struct device *dev, struct nouveau_platform_gpu *gpu) { @@ -158,6 +160,20 @@ static void nouveau_platform_remove_iommu(struct device *dev, } } +#else + +static void nouveau_platform_probe_iommu(struct device *dev, + struct nouveau_platform_gpu *gpu) +{ +} + +static void nouveau_platform_remove_iommu(struct device *dev, + struct nouveau_platform_gpu *gpu) +{ +} + +#endif + static int nouveau_platform_probe(struct platform_device *pdev) { struct nouveau_platform_gpu *gpu;
The lack of IOMMU API support can make nouveau_platform_probe_iommu() fail to compile because struct iommu_ops is then empty. Fix this by skipping IOMMU probe in that case - lack of IOMMU on platform devices is sub-optimal, but is not an error. Signed-off-by: Alexandre Courbot <acourbot@nvidia.com> --- This is an alternative to https://lkml.org/lkml/2015/5/19/484. Most users of Nouveau do not care about IOMMU support, so we should not impose that option on them. drm/nouveau/nouveau_platform.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+)