Re: [PATCH] media: imx219: Report streams using frame descriptors

[Laurent Pinchart]

On Thu, Jun 11, 2026 at 04:06:38PM +0300, Tomi Valkeinen wrote:
> On 11/06/2026 12:24, Sakari Ailus wrote:
> > On Thu, Jun 11, 2026 at 12:13:02PM +0300, Tomi Valkeinen wrote:
> >> From: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> >>
> >> Implement the .get_frame_desc() subdev operation to report information
> >> about streams to the connected CSI-2 receiver. This is required to let
> >> the CSI-2 receiver driver know about virtual channels and data types for
> >> each stream.
> >>
> >> Signed-off-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
> >> Reviewed-by: Jacopo Mondi <jacopo.mondi@xxxxxxxxxxxxxxxx>
> >> [tomi.valkeinen: picked from "Generic line based metadata support, internal pads" series]
> >> Signed-off-by: Tomi Valkeinen <tomi.valkeinen@xxxxxxxxxxxxxxxx>
> >> ---
> >> This patch that adds .get_frame_desc() support to imx219 driver has been
> >> circulating for a few years, and is currently posted in "[PATCH v12
> >> 00/86] Generic line based metadata support, internal pads" series.
> >>
> >> However, as some bridge drivers require modern drivers that support
> >> .get_frame_desc, specifically ds90ub960.c, let's pick the patch and
> >> queue it separately from the huge metadata series.
> > 
> > I've been recently working on
> > <URL:https://lore.kernel.org/linux-media/20260518164318.3367888-1-sakari.ailus@xxxxxxxxxxxxxxx/>.
> > In other words, drivers that have a single stream don't need this. We could
> 
> Thanks, I had missed that. I like the idea of a helper that does the 
> fallback mechanism. But I wonder about the need for dynamic alloc, which 
> complicates the series. In any case, we can drop this series and 
> continue the discussion on your series.

Maybe we can merge the fallback implementation separately from the
dynamic allocation if the latter requires more work ? I'm also not a fan
of the dynamic allocation, at least in the way it's implemented in the
proposed series. I'm wondering if we could build the frame descriptors
at stream enable time and store it in state structures instead.

-- 
Regards,

Laurent Pinchart