linux-kernel - Re: [PATCH v2 0/8] Add AMD ISP4 driver

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Message-ID: <aKfqVNk_WSEeBxlz@sultan-box>
Date: Thu, 21 Aug 2025 20:56:04 -0700
From: Sultan Alsawaf <sultan@...neltoast.com>
To: "Du, Bin" <bin.du@....com>
Cc: mchehab@...nel.org, hverkuil@...all.nl,
	laurent.pinchart+renesas@...asonboard.com,
	bryan.odonoghue@...aro.org, sakari.ailus@...ux.intel.com,
	prabhakar.mahadev-lad.rj@...renesas.com,
	linux-media@...r.kernel.org, linux-kernel@...r.kernel.org,
	pratap.nirujogi@....com, benjamin.chan@....com, king.li@....com,
	gjorgji.rosikopulos@....com, Phil.Jawich@....com,
	Dominic.Antony@....com,
	Mario Limonciello <mario.limonciello@....com>, Richard.Gong@....com,
	anson.tsao@....com
Subject: Re: [PATCH v2 0/8] Add AMD ISP4 driver

On Fri, Aug 22, 2025 at 10:23:48AM +0800, Du, Bin wrote:
> On 8/14/2025 2:53 PM, Sultan Alsawaf wrote:
> > On Wed, Jun 18, 2025 at 05:19:51PM +0800, Bin Du wrote:
> > > AMD ISP4 Key features:
> > > - Processes bayer raw data from the connected sensor and output them to different YUV formats
> > > - Downscale input image to different output image resolution
> > > - Pipeline to do image processing on the input image including demosaic, denoise, 3A, etc
> > 
> > BTW, another problem I have which I would love some help with: may I get the FW
> > commands for setting basic 3A parameters?
> > 
> > It seems like the default AE mode does frame-averaging, which is really
> > unsuitable for video calls on the webcam. My face is really underexposed as a
> > result during the daytime because there's a lot of ambient light in the
> > background.
> > 
> > The webcam on this laptop also has a very wide field of view, which makes my
> > face appear small and shows too much of the background. This also exacerbates
> > the AE problem.
> > 
> > I'm thinking CMD_ID_SET_ZOOM would fix the FOV problem, and then either
> > CMD_ID_AE_SET_MODE to change the AE mode or CMD_ID_AE_SET_REGION to set the AE
> > ROI would fix the exposure problem. What do you think?
> > 
> > Thanks,
> > Sultan
>
> Thanks Sultan for the suggestion, sorry for the late response because we
> spent some time internally to discuss the feasibility.

Thanks for looking into this!

> Yes, it's really good suggestion. Because current V4l2 doesn't have standard
> ioctl for like region setting, to support it, besides adding FW command, new
> customized ioctl also needs be added and no existing APP can benefit from
> it. So our idea is not to add them to our current upstream driver, but we
> would be really glad to help you to enable them locally with dedicated
> thread, suppose it can help to improve the IQ with correct input setting
> like the correct ROI region, but we aren't sure because we didn't do that
> before on Linux and would really expect your test result and feedback.

I'm happy to help develop this and even help write the code. :)

I think a lot of useful functionality can be put upstream just through V4L2,
like V4L2_CID_EXPOSURE_METERING to control the AE mode.

For advanced functions that don't have a standard V4L2 control, maybe we can set
some defaults in the driver to improve the experience for front-facing cameras,
i.e. webcams.

Depending on the features exposed by FW, maybe setting a ROI for AE isn't
necessary. Is it possible for the FW to do face detection and set 3A according
to the face landmarks/ROI?

Thanks,
Sultan