[PATCH 0/3] NVIDIA Tegra210 NVJPG support

[Mikko Perttunen]

On 6/10/25 6:05 PM, Thierry Reding wrote:
> On Fri, Jun 06, 2025 at 11:45:33AM +0100, Diogo Ivo wrote:
>> Hello,
>>
>> This series adds support for the NVJPG hardware accelerator found in the
>> Tegra210 SoC.
>>
>> The kernel driver is essentially a copy of the NVDEC driver as both
>> engines are Falcon-based.
>>
>> For the userspace part I have written a Mesa Gallium backend [1] that,
>> while still very much experimental, works in decoding images with VA-API.
>>
>> I have been using ffmpeg to call VA-API with the following command:
>>
>> ffmpeg -v verbose -hwaccel vaapi -hwaccel_device /dev/dri/renderD129 -i <input.jpg> -pix_fmt bgra -f fbdev /dev/fb0
>>
>> which decodes <input.jpg> and shows the result in the framebuffer.
>>
>> The firmware for the engine can be obtained from a Linux for Tegra
>> distribution.
> 
> By the way, have you tried running this on anything newer than Tegra210?
> Given your progress on this, we can probably start thinking about
> submitting the binaries to linux-firmware.

FWIW, the impression I have is that NVJPG is basically unchanged all the 
way to Tegra234. So if we add stream ID support and the firmwares, it'll 
probably just work. Tegra234 has the quirk that it has two instances of 
NVJPG -- these have to be distinguished by their different class IDs. 
But we should go ahead with the T210 support first.

> 
>> Due to the way the Gallium implementation works for Tegra
>> the GPU also needs to be enabled.
> 
> I wonder if maybe we can get rid of this requirement. While it's
> certainly nice to have the GPU enabled, there may be cases where using
> only the other engines may be advantageous. Originally when I had worked
> on VIC, I was looking at how it could be used for compositing without
> getting the GPU involved. That's something that Android devices tend(ed)
> to do because of the power savings that come with it.
> 
> Anyway, not a big deal, depending on the GPU for now is fine.
> 
> Thierry