On 24/07/2019 15:09, Dmitry Osipenko wrote:
24.07.2019 17:03, Yuehaibing пишет:
On 2019/7/24 21:49, Robin Murphy wrote:
On 24/07/2019 11:30, Sakari Ailus wrote:
Hi Yue,
On Mon, Jul 22, 2019 at 09:47:49PM +0800, YueHaibing wrote:
If IOMMU_SUPPORT is not set, ipu3 driver may select IOMMU_IOVA to m.
But for many drivers, they use "select IOMMU_IOVA if IOMMU_SUPPORT"
in the Kconfig, for example, CONFIG_TEGRA_VDE is set to y but IOMMU_IOVA
is m, then the building fails like this:
drivers/staging/media/tegra-vde/iommu.o: In function `tegra_vde_iommu_map':
iommu.c:(.text+0x41): undefined reference to `alloc_iova'
iommu.c:(.text+0x56): undefined reference to `__free_iova'
Reported-by: Hulk Robot <hulkci@xxxxxxxxxx>
Fixes: 7fc7af649ca7 ("media: staging/intel-ipu3: Add imgu top level pci device driver")
Signed-off-by: YueHaibing <yuehaibing@xxxxxxxxxx>
---
drivers/staging/media/ipu3/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/staging/media/ipu3/Kconfig b/drivers/staging/media/ipu3/Kconfig
index 4b51c67..b7df18f 100644
--- a/drivers/staging/media/ipu3/Kconfig
+++ b/drivers/staging/media/ipu3/Kconfig
@@ -4,7 +4,7 @@ config VIDEO_IPU3_IMGU
depends on PCI && VIDEO_V4L2
depends on MEDIA_CONTROLLER && VIDEO_V4L2_SUBDEV_API
depends on X86
- select IOMMU_IOVA
+ select IOMMU_IOVA if IOMMU_SUPPORT
This doesn't seem right: the ipu3-cio2 driver needs IOMMU_IOVA
independently of IOMMU_SUPPORT.
Looking at tegra-vde, it seems to depend on IOMMU_SUPPORT but that's not
declared in its Kconfig entry. I wonder if adding that would be the right
way to fix this.
Cc'ing the IOMMU list.
IOMMU_SUPPORT is optional for the Tegra-VDE driver.
Right, I also had the impression that we'd made the IOVA library completely standalone. And what does the IPU3 driver's Kconfig have to do with some *other* driver failing to link anyway?
I can see it failing if IPU3 is compiled as a loadable module, while
Tegra-VDE is a built-in driver. Hence IOVA lib should be also a kernel
module and thus the IOVA symbols will be missing during of linkage of
the VDE driver.
Oh, I misunderstand that IOMMU_IOVA is depend on IOMMU_SUPPORT, thank you for clarification.
I will try to fix this in tegra-vde.
Probably IOVA could be selected independently of IOMMU_SUPPORT, but IOVA
library isn't needed for the VDE driver if IOMMU_SUPPORT is disabled.
Oh, I think I get the problem now - tegra-vde/iommu.c is built
unconditionally and relies on the static inline stubs for IOMMU and IOVA
calls if !IOMMU_SUPPORT, but in a compile-test config where IOVA=m for
other reasons, it then picks up the real declarations from linux/iova.h
instead of the stubs, and things go downhill from there. So there is a
real issue, but indeed it's Tegra-VDE which needs to be restructured to
cope with such configurations, and not IPU3's (or anyone else who may
select IOVA=m in future) job to work around it.
Robin.
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