Sergey Zakharchenko <doublef.mobile@xxxxxxxxx>: > Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>: > > Do you think it would make sense to do this by default, without > > requiring a quirk ? Or are there cases where this calculation would lead > > to incorrect results while the bpp reported by the camera would be right > > ? > > The loop is a simplified version of the v4l2_fill_pixfmt() loop. The > calculation might need some checking, and might be invalid, in case > block_w/block_h format fields are significant (not 0 and not 1), > because then effective bits-per-pixel would seemingly be fractional, > and depend on the image dimensions if they weren't aligned; however I > see no formats using the block_w/block_h fields defined so far. It's likely possible to directly replace the bpp-using computation in https://github.com/torvalds/linux/blob/2874c5fd284268364ece81a7bd936f3c8168e567/drivers/media/usb/uvc/uvc_driver.c#L636 with a call to v4l2_fill_pixfmt() and the sizeimage it returns. However, bpp is used elsewhere, and it's hard to tell what it should be taken to be to in the hypothetical exotic cases I'm considering, so I'm reluctant to go that route. I'm going to send v3 in an hour unless there are other suggestions. Best regards, -- Sergey Zakharchenko Digital Loggers, Inc.
