Jordan Crouse <jorcrous@xxxxxxxxxx> writes: > On Tue, Mar 07, 2023 at 05:20:18PM +0100, Enric Balletbo i Serra wrote: [...] >> > >> > But regardless, I think that it would be better for a driver to >> > not change the order of advertised VIDIOC_ENUM_FMT pixel formats. >> > >> > Because what happens now is that a decoding that was previously >> > working by default is not working anymore due a combination of >> > the default being changed and S_FMT not working as expected. > > For my part, I was using the gstreamer v4l2 decoder which for some reason tries > to verify it can support whatever format it gets with G_FMT *before* > trying a S_FMT. I can't confirm or deny if S_FMT currently works or not. > > That said, I entirely agree with Javier. While it might be more > bandwidth efficient, QC08C is a obscure format. It is far more likely that the > average open source user would rather use a well known output format and, as > has been mentioned, once S_FMT is fixed those in the know can use the other > formats if they are working with other Qualcomm hardware blocks. > Agreed. The rule is that the kernel shouldn't regress user-space and the patches that changed the default format certainly did that. So from that point of view I think that this patch should land. There's also Enric's point that NV12 is a more common format and supported by more user-space programs. That's why think that regardless of the S_FMT situation, makes sense to revert to the previous default behaviour. -- Best regards, Javier Martinez Canillas Core Platforms Red Hat
