[PATCH 0/3] NVIDIA Tegra210 NVJPG support

[Thierry Reding]

On Wed, Jun 11, 2025 at 01:04:14PM +0100, Diogo Ivo wrote:
> 
> 
> On 6/10/25 10:05 AM, 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.
> 
> Since I don't have access to other Tegra platforms I haven't been able
> to test this driver there. For this I need help from someone with access
> to more hardware, I can send a version that just adds the extra compatibles
> and we could see if it works.
> 
> As for the firmwares that would be great!

I think both of these are things that Mikko and I can help with.

> > > 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.
> 
> Yes I think this is possible to do, it mainly has involves properly
> handling the Gallium driver initialization. I'll take a look at it
> before submitting the MR for the Gallium driver.

Okay, great. But I think it's definitely something that we can defer if
it's non-trivial.

Thierry
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