Re: [PATCH] ARM: dts: exynos5422-odroid*: remove fimd node

[Krzysztof Kozlowski <k.kozlowski@samsung.com>]

On 23.11.2015 22:56, Javier Martinez Canillas wrote:
> Hello Krzysztof,
> 
> On 11/10/2015 09:43 PM, Krzysztof Kozlowski wrote:
> 
> [snip]
> 
>>
>>
>> BTW, do you know why we don't have EXYNOS_IOMMU enabled in defconfig?
>> Any reasons against?
>>
> 
> It was explicitly disabled by commit 6562f3bd396a ("ARM: exynos_defconfig:
> Disable IOMMU support") because Exynos IOMMU support was broken and caused
> a BUG on boot, the discussion of the patch is [0].

Right, now I remember.


> But I just tested booting a v4.4-rc2 kernel on an Exynos5800 Peach Pi with
> Exynos IOMMU enabled and the machine boots, display is working and
> /sys/kernel/iommu_grups/*/devices shows that the devices were correctly
> attached to an IOMMU group so things seems to have been sorted out now.
> 
> So it seems that EXYNOS_IOMMU could be enabled again. It would be good to
> give such a patch a spin at kernelci before posting IMHO though just to be
> sure there are no issues remaining.

Yes for enabling. No for testing only on kernelci. Booting is not a
sufficient test in this case. I would expect testing also display - at
least some frame buffer console on DP or HDMI (or whatever output could
be generated... Xorg/Wayland would be better of course). You need it
because display and camera (including complementary modules like JPEG,
MFC etc) are actually the only users of Exynos IOMMU in mainline.

Best regards,
Krzysztof