How to fix Linux CMA on x86 with internal graphic card i915/hda_intel ioremap error?

How to fix Linux CMA on x86 with internal graphic card i915/hda_intel ioremap error?

[Suesens, Sebastian]

Hello,

I enabled the CMA (CONFIG_CMA=y) for an x86 machine on Linux kernel v5.10 and v5.15 When I boot the system the CMA reserved memory, but when the graphic card driver i915 or hda_intel is loaded the system crashed. 
I see that ioremap on RAM at 0x0000000000000000 - 0x00000000d0000000 get fail. When I blacklist the i915 and hda_intel module the system boots fine with cma memory reserved.

I think this has something to do with the shared memory which this driver use.
 
Does anyone know if a kernel config or something else prevents this crash? 

Please answer me in CC.

Regards Sebastian

Re: How to fix Linux CMA on x86 with internal graphic card i915/hda_intel ioremap error?

[Jani Nikula]

On Thu, 28 Mar 2024, "Suesens, Sebastian" <sebastian.suesens@zeiss.com> wrote:
> Hello,
>
> I enabled the CMA (CONFIG_CMA=y) for an x86 machine on Linux kernel v5.10 and v5.15 When I boot the system the CMA reserved memory, but when the graphic card driver i915 or hda_intel is loaded the system crashed. 
> I see that ioremap on RAM at 0x0000000000000000 - 0x00000000d0000000 get fail. When I blacklist the i915 and hda_intel module the system boots fine with cma memory reserved.
>
> I think this has something to do with the shared memory which this driver use.
>  
> Does anyone know if a kernel config or something else prevents this crash? 

If you can reproduce this with recent kernels, please file a bug as
described at [1].

BR,
Jani.

[1] https://drm.pages.freedesktop.org/intel-docs/how-to-file-i915-bugs.html

-- 
Jani Nikula, Intel