Re: [PATCH 3/5] media: dt-bindings: Add Apple ISP

On February 19, 2025 12:05:29 PM GMT+01:00, Sasha Finkelstein [off-list ref] wrote:

On Wed, 19 Feb 2025 at 11:53, Laurent Pinchart
[off-list ref] wrote:

quoted

quoted

Those are board-specific and not discoverable via the ISP protocol.

But they are settable through the ISP protocol, aren't they ? For
instance, looking at isp-imx248.dtsi, the first four entries are

        /* 1280x720 */
        preset0 {
                apple,config-index = <0>;
                apple,input-size = <1296 736>;
                apple,output-size = <1280 720>;
                apple,crop = <8 8 1280 720>;
        };

        /* 960x720 (4:3) */
        preset1 {
                apple,config-index = <0>;
                apple,input-size = <1296 736>;
                apple,output-size = <960 720>;
                apple,crop = <168 8 960 720>;
        };

        /* 960x540 (16:9) */
        preset2 {
                apple,config-index = <0>;
                apple,input-size = <1296 736>;
                apple,output-size = <960 540>;
                apple,crop = <8 8 1280 720>;
        };

        /* 640x480 (4:3) */
        preset3 {
                apple,config-index = <0>;
                apple,input-size = <1296 736>;
                apple,output-size = <640 480>;
                apple,crop = <168 8 960 720>;
        };

But I may be interested in capturing a 640x480 frame with cropping only
and without scaling, with

input-size = 1296x736
output-size = 640x480
crop = (328,128)/640x480

Or I may want my cropped frame to be located in the upper-left corner:

input-size = 1296x736
output-size = 640x480
crop = (8,8)/640x480

If I set those parameters through the ISP protocol, won't it work ?

--
Regards,

Laurent Pinchart

For cropping - you do not want to change those parameters, the sensor
is partially occluded, and the crop area is specified in such a way
to not expose those pixels. As for scaling - we can expose only the 1:1
scale and let userspace deal with it, but it appears that it expects
the other common output sizes to exist.

The square sensor with the hack is the IMX558. The configs there are actually a workaround for missing ANE support.

What the driver is supposed to be doing is using the higher numbered presets, which crop internally and exclude the occluded area. But those on machines with that sensor end up requiring ANE integration for denoising and ISP crashes without it.

Config #0 doesn't use ANE, so the crops are re-creations of the other configs so it behaves the same minus the denoising.