[PATCH 3/3] drm/amdgpu/vcn: Add parameter to force (en/dis)abling indirect SRAM mode

[Guilherme G. Piccoli]

On 17/01/2023 13:24, Limonciello, Mario wrote:
> [...]
>>> Though I see two problems with that: first, I'm not sure what's the
>>> impact in the GPU functioning when I disable some IP block.
>>>
> 
> It depends on the individual block what the impact is.  For example
> if you don't have VCN, then you can't do any accelerated video playback.
> 
>>> Second, the parameter is a bit hard to figure - we need to clear a bit
>>> for the IP block we want to disable, and the doc suggest to read on
>>> dmesg to get this information (it seems it changes depending on the HW
>>> model), but I couldn't parse the proper bit from dmesg. Needed to
>>> instrument the kernel to find the proper bit heh
>>>
> 
> Isn't it this stuff (taken from a CZN system):
> 
> [    7.797779] [drm] add ip block number 0 <soc15_common>
> [    7.797781] [drm] add ip block number 1 <gmc_v9_0>
> [    7.797782] [drm] add ip block number 2 <vega10_ih>
> [    7.797783] [drm] add ip block number 3 <psp>
> [    7.797783] [drm] add ip block number 4 <smu>
> [    7.797784] [drm] add ip block number 5 <dm>
> [    7.797785] [drm] add ip block number 6 <gfx_v9_0>
> [    7.797786] [drm] add ip block number 7 <sdma_v4_0>
> [    7.797787] [drm] add ip block number 8 <vcn_v2_0>
> [    7.797788] [drm] add ip block number 9 <jpeg_v2_0>
> 
> So for that system it would be bit 8 to disable vcn.
> 
> In terms of how debugging would work:
> I would expect when you get your failure it will have been the previous
> block # that failed, and so you can reboot with that block masked and
> see if you get further.
> 

Thanks Mario, much appreciated! You're totally right and I messed up not
seeing these obvious messages...

So, I'll just drop the parameter on V2.
Cheers,


Guilherme