Hello Krzysztof,
On 11/24/2015 12:50 AM, Krzysztof Kozlowski wrote:
> 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
Sorry if I didn't explain myself clearly. I didn't mean that kernelci was
enough to test Exynos IOMMU support, what I said is that would be nice to
have some boot coverage besides the normal manual (or automated) display
testing that someone could do on available platforms as discussed over IRC.
> 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
Yes, as I mentioned in the previous email, I tested display (with X) on an
Exynos5800 Peach Pi. I don't have a rootfs with wayland/weston handy but I
could prepare one tomorrow to give a try.
> because display and camera (including complementary modules like JPEG,
> MFC etc) are actually the only users of Exynos IOMMU in mainline.
>
Do you have some test cases for MFC? I know that Gstreamer has support
for it but I don't know what Gst pipelines I can use to test if all is
working correctly.
> Best regards,
> Krzysztof
>
Best regards,
--
Javier Martinez Canillas
Open Source Group
Samsung Research America
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