[PATCH] gpu: host1x: Skip reset assert on Tegra186

[Mikko Perttunen]

On 2/16/24 19:02, Thierry Reding wrote:
> On Wed Feb 14, 2024 at 12:40 PM CET, Mikko Perttunen wrote:
>> From: Mikko Perttunen <mperttunen at nvidia.com>
>>
>> On Tegra186, other software components may rely on the kernel to
>> keep Host1x operational even during suspend. As such, as a quirk,
>> skip asserting Host1x's reset on Tegra186.
> 
> This all sounds a bit vague. What other software components rely on the
> kernel to keep host1x operational during suspend? And why do they do so?
> Why is this not a problem elsewhere?

My assumption is that it's due to a secure world application accessing 
NVDEC or display engines during suspend or resume. This happening 
without kernel knowledge is a bad thing, but it's hard to change at this 
point.

The reset line (CAR vs BPMP vs non-accessible reset line), and the 
secure application code programming this stuff is slightly different in 
every chip generation, which is where I think the differences happen.

Mikko

> 
> Thierry