radeon: Force loading with no microcode - will it damage any hardware?

[Alex Deucher]

On Mon, May 14, 2018 at 4:47 AM, Michel Dänzer <michel at daenzer.net> wrote:
> On 2018-05-13 06:22 AM, Damien Zammit wrote:
>> Can someone with some AMD gpu hardware expertise please advise whether
>> forcing cards to continue loading regardless if microcode is missing
>> will do damage to hardware long term, for the cards supported by
>> 'radeon' driver?
>>
>> I have heard from someone that it might just be for the 3d CP unit only,
>> which might just disable 3d graphics if the microcode is missing on r600
>> and rv770.
>
> The drivers fail without the microcode because they can't work without
> it, it's nothing to do with damaging hardware.
>
>
>> I want to know if it's okay so we can get basic 2D support in libre
>> kernels where the microcode is deblobbed, even though I know it's
>> generally not recommended to omit microcode for all kinds of reasons.
>
> There is no 2D-only acceleration support in >= R600 hardware anyway.

Even on older hardware, the mmio support was not validated by internal
teams during bring up so on r3xx-r5xx we ran into hangs when
attempting to use the mmio paths since some of the relevant
synchronization registers were only accessible via the CP.  Also the
driver was never validated without firmware loaded so you may run into
problematic cases due to lack of testing.

Alex