[Nouveau] Problems getting nouveau to work with either Geforce GT710 or Geforce 9800GT on ARM Cortex-A9

[Luís Mendes]

Hi Ben,

Thanks for your reply.
My replies follow in between.

Luís

On Thu, Jan 25, 2018 at 5:40 AM, Ben Skeggs <skeggsb at gmail.com> wrote:
> On 24 January 2018 at 06:19, Luís Mendes <luis.p.mendes at gmail.com> wrote:
>> Hi Arnd,
>>
>> Sorry for sending this email directly to you, but maybe you can help
>> me, or guide me where to look for.
>>
>> I am having big trouble getting the nouveau driver to work with either
>> Geforce GT 710 or Geforce 9800 GT on an ARM armv7l Cortex-A9 with PCIe
>> x1/x4 with linux kernel 4.15-rc.
>>
>> The Geforce GT 710 hangs the kernel boot process for a while and then
>> a kernel oops occurs, due to nvidiafb, when initializing CRTC. It also
>> generates messages "division by zero in kernel".
> You definitely want to disable nvidiafb somehow, it's ancient,
> unmaintained, and has zero chance of working on this hardware.  I'm
> not even entirely sure how/why it thinks it can work on this hardware,
> but just disable it.

I was unaware of that. I'll disable it and report back the results.

>
>>
>> The nouveau module generates a gpu lockup with Geforce 9800GT, DMA
>> transfers seem to fail, but sometimes is possible to start lightdm and
>> enter the login screen with an all black screen with just the mouse
>> cursor visible.
>>
>> I've also tried AMD RX460 and Radeon R7 240 graphics cards on the same
>> hardware with the same Linux kernel and I am able to enter Ubuntu Mate
>> 17.10 Desktop and run glmark and other applications, so I am sure the
>> hardware is capable of working with NVIDIA cards too, but the nouveau
>> module somehow doesn't cope well with the armv7l architecture, maybe
>> lock handling, irqs, dma fences, I don't know for sure.
> I'm not entirely sure what else is going on here.  Is that
> architecture big/little-endian?  We very likely have some issues on
> big-endian particularly with newer hardware, where the endian controls
> have either moved or disappeared.

I'm running Linux with ARM SoC in little endian mode (armv7l).

>
> The driver supposedly works on Tegra ARM architectures with PCIE
> devices, so hopefully there's not too much to do here to get it
> working for you.

Great! I appreciate any insight, or help you can give on this.

>
> Ben.
>
>>
>> I am a software and hardware engineer using Linux on a daily basis for
>> quite some time now, so that I am able to provide more details, try
>> patches, or make changes to kernel source to try to fix this, but I
>> would need some insight where to look for. Maybe you can help or
>> redirect me to someone who can help me...
>>
>> I've attached the kernel logs from both graphics cards issues.
>>
>> Regards,
>> Luís Mendes
>>
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