[PATCH] drm: Harmonize CIK ASIC support in radeon and amdgpu (v2)

[Shawn Starr]

On 04/11/2017 12:16 PM, Christian König wrote:
> Am 11.04.2017 um 18:05 schrieb Felix Kuehling:
>> On 17-04-11 12:01 AM, Michel Dänzer wrote:
>>> One issue with this per-driver enable_cik option is that if the user
>>> only enables it in the driver where it's disabled by default, without
>>> also disabling it in the driver where it's enabled by default, it's back
>>> to the current situation where both drivers try to use the same GPUs,
>>> and it's up to chance which one actually gets to.
>>>
>>> That's why I was thinking about also having a shared command line option
>>> respected by both drivers, e.g. amd_cik_driver=amdgpu/radeon . That
>>> would be the preferred way to choose the driver at runtime.
>> The shared option could not be in either amdgpu or radeon. Otherwise
>> we'd create a cross-dependency between the drivers. It would have to be
>> in drm, I guess?
>
> Yes, but to be honest that sounds more and more like shooting with
> cannonballs on birds to me.
>
> At least I was fine with the per driver config option.
>
> Regards,
> Christian.
>
>>

Any reason we can't just rip out the PCI IDs for CIK in radeon? If 
distros then can enable both drivers the kernel will load the correct 
one based on where the PCI IDs are being probed?

Or are there drm ioctl issues that make that incompatible?

Thanks,
Shawn

>>> Note that the per-driver enable_cik option will still be needed to be
>>> able to override the kernel command line when manually loading the
>>> drivers.
>> Why? I could make the shared option writable in
>> /sys/module/drm/parameters/amd_cik_driver so you can change it before
>> loading the module.
>>
>> Regards,
>>    Felix
>>
>>> Maybe there's a better way to handle both cases that I haven't
>>> thought of.
>>>
>>>
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>
>
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