mainline/master boot bisection: v4.15-rc3 on peach-pi #3228-staging

[Shuah Khan]

On 12/11/2017 04:02 PM, Russell King - ARM Linux wrote:
> On Mon, Dec 11, 2017 at 10:58:29PM +0000, Russell King - ARM Linux wrote:
>> On Mon, Dec 11, 2017 at 11:54:48PM +0100, Javier Martinez Canillas wrote:
>>> So I gave a quick look to this, and at the very least there's a bug in
>>> the Exynos5800 Peach Pi DTS caused by commit 1cb686c08d12 ("ARM: dts:
>>> exynos: Add status property to Exynos 542x Mixer nodes").
>>>
>>> I've posted a fix for that:
>>>
>>> https://patchwork.kernel.org/patch/10105921/
>>>
>>> I believe this could be also be the cause for the boot failure, since
>>> I see in the boot log that things start to go wrong after exynos-drm
>>> fails to bind the HDMI component:
>>>
>>> [ 2.916347] exynos-drm exynos-drm: failed to bind 14530000.hdmi (ops
>>> 0xc1398690): -1
>>
>> Umm, -1 ?  Looking that error code up in
>> include/uapi/asm-generic/errno-base.h says it's -EPERM.
>>
>> I suspect that's someone just returning -1 because they're lazy...
>> which is real bad form and needs fixing.
> 
> Oh, it really is -EPERM:
> 
> struct exynos_drm_crtc *exynos_drm_crtc_get_by_type(struct drm_device *drm_dev,
>                                        enum exynos_drm_output_type out_type)
> {
>         struct drm_crtc *crtc;
> 
>         drm_for_each_crtc(crtc, drm_dev)
>                 if (to_exynos_crtc(crtc)->type == out_type)
>                         return to_exynos_crtc(crtc);
> 
>         return ERR_PTR(-EPERM);
> }
> 
> Does "Operation not permitted" really convey the error here?  It doesn't
> look like a permission error to me.
> 
> Can we please avoid abusing errno codes?

I tried 4.15-rc3 on odroid-xu4 after seeing drm issues reported. 4.15-rc2+
with top commit g968edbd worked just fine for me last Friday. I ran several
tests and everything checked out except the exynos-gsc lockdep issue I sent
a 4.14 patch for.

However, with 4.15-rc3, dmesg is gets filled with 

[  342.337181] [drm] Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer
[  342.337470] [drm] Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer
[  342.337851] [drm] Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer
[  402.382346] [drm] Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer
[  402.396682] [drm] Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer
[  402.399244] [drm] Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer
[  402.399496] [drm] Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer
[  402.399848] [drm] Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer
[  402.400163] [drm] Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer
[  402.400495] [drm] Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer
[  402.401294] [drm] Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer
[  402.401595] [drm] Non-contiguous allocation is not supported without IOMMU, falling back to contiguous buffer

Something broke in 4.15-rc3 on odroix-xu4 badly with exynos_defconfig.

I will start bisect and try to isolate the problem. I suspect this is related to dts
changes perhaps? I used to this problem a while back and it has been fixed.

thanks,
-- Shuah