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

[Alex Deucher]

On Tue, Jan 17, 2023 at 9:33 AM Guilherme G. Piccoli
<gpiccoli at igalia.com> wrote:
>
> On 16/01/2023 23:33, Limonciello, Mario wrote:
> > [...]
> >
> > For debugging these type of problems, I think an effective debugging
> > tactic would have been to mask the IP block (amdgpu.ip_block_mask).
>
> Thank you, it worked indeed - nice suggestion!
>
> 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.
>
> 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
>
> The second part is easy to improve (we can just show this bit in
> dmesg!), I might do that instead of proposing this parameter, which
> seems didn't raise much excitement after all heheh
>
> Finally, I'm still curious on why Deck was working fine with the
> indirect SRAM mode disabled (by mistake) in many kernels - was it in
> practice the same as disabling the VCN IP block?

IIRC, it depends on the fuse recipe for the particular ASIC.

Alex


>
> Thanks,
>
>
> Guilherme
>