On February 19, 2025 12:05:29 PM GMT+01:00, Sasha Finkelstein <fnkl.kernel@xxxxxxxxx> wrote:
>On Wed, 19 Feb 2025 at 11:53, Laurent Pinchart
><laurent.pinchart@xxxxxxxxxxxxxxxx> wrote:
>> >
>> > 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.
