Hi, On 1/29/24 09:58, Jacopo Mondi wrote: > Hi Hans > > On Sun, Jan 28, 2024 at 09:58:41PM +0100, Hans de Goede wrote: >> Hi All, >> >> While adding vblank ctrl support to the ov2680 driver I was looking >> at the vblank ctrl code in the ov5693 and I noticed something >> which I believe is weird / undesirable. >> >> When setting a new mode the ov5693 driver does not keep the current >> vts value (adjusting vblank to keep vts and thus the framerare and >> exposure unchanged). >> >> Instead it calculates a new vts value, resetting the framerate >> to 30 fps; or 60 fps for smaller resolutions and then sets >> vblank to the new (vts - new_mode->height) and adjusts >> the exposure control-range to fit within the new vts, potentially >> also changing the exposure value. >> >> This behavior of the ov5693 code means that switching resolution >> also changes the framerate and the exposure value which seems >> undesirable. >> >> The vblank and hblank control values changes on setting a mode >> is unavoidable but the framerate and exposure value changing >> at the same time seems undesirable. >> >> Note that this also halves the max supported exposure value >> when going to a lower-res mode even when userspace never >> touches the vblank control. >> > > Would you be interested in reviewing > https://patchwork.kernel.org/project/linux-media/list/?series=697777&state=%2A&archive=both > > and discuss there what the desired behaviour should be ? I'm definitely interested in discussing this and in helping with reviewing the documentation patches, good timing wrt writing those patches :) but Dan already replied in this thread, so lets keep the discussion in this thread for now ? Also I think this will probably make a good agenda item for the libcamera workshop coming Friday ? Hopefully we can make some decisions about this there and then I can help with reviewing revised documentation patches after that. Regards, Hans
