Hi Hans, thanks for your reply. I understand your point of view. Since the sn9c102 will be removed from the kernel soon, I am considering another option, that is to move the driver to UV4L, which is a transparent, ~100% userspace implementation of V4L2-compliant drivers for input devices. So, for those who are still interested in good support for the sn9cxxx, I'll be porting all the code to userspace. Users will not notice any difference from a kernel driver. Fore more informations: http://linux-projects.org Regards, Luca In data domenica 15 dicembre 2013 12:18:17, Hans Verkuil ha scritto: > Hi Luca, > > On 12/14/2013 06:13 PM, Luca Risolia wrote: > >> From: Hans Verkuil <hans.verkuil@xxxxxxxxx> > >> > >> During the last media summit meeting it was decided to move this driver > >> to > >> staging as the first step to removing it altogether. > >> > >> Most webcams covered by this driver are now supported by gspca. Nobody > >> has > >> the hardware to convert the remaining devices to gspca. > > > > I have all the boards given by the manufacturer. Last time I tried the > > gspca driver it certainly did not work with most of the sn9c1xx-based > > models the gspca driver claims to be supporting (which were a subset of > > the devices actually supported by sn9c102). > > > >> This driver needs a major overhaul to have it conform to the latest > >> frameworks and compliancy tests. > > > > What is not compliant? I will offer my help to update the driver in case > > but cannot give my help to fix or test all the boards again with the > > gspca, as it would be a considerable amount of extra work. > > Work is ongoing to move all drivers to the latest V4L2 frameworks (control > framework, using v4l2_fh, v4l2_device, video_ioctl2 & unlocked_ioctl, > videobuf2 were possible). This reduces code complexity of the drivers and > will eventually allow us to get rid of old core legacy code. In addition, > using these frameworks will help drivers to pass the v4l2-compliance test > tool (part of v4l-utils.git). > > For most drivers not yet converted I have hardware myself that I can use to > do the conversion and testing, but not for the sn9c102. > > Given the fact that that driver caters to very old webcams that few people > use, and for which cheap modern webcam replacements are easily available, > it is the opinion of the core v4l2 developers that it is not worth the > effort for us to convert the driver. > > The first step in that process is to move it to staging to signal that > unless something is done this driver will be removed. > > There are a number of options: > > 1) Nothing is done. In that case the driver will be removed, probably end of > next year. > 2) You convert the driver to the various frameworks, make it pass > v4l2-compliance, etc. In that case there is no reason to remove it. > 3) My estimate is that option 2) is time consuming. It might be easier for > you to add support for the webcams to gspca instead. > 4) Send the webcams that are not (or not correctly) supported by gscpa to > Hans de Goede, and let him add support for them to gspca. I don't know if > he wants to, though. He may well decide that it is not worth it, although I > assume he would be willing to at least fix gspca for webcams that are not > correctly supported. > > >> Without hardware, however, this is next to impossible. Given the fact > >> that > >> this driver seems to be pretty much unused (it has been removed from > >> Fedora > >> several versions ago and nobody complained about that), we decided to > >> drop > >> this driver. > > > > As no one has the hardware, what is the reason why the sn9c102 has been > > moved into gspca, although the sn9c102 driver has been already present in > > the kernel since years before? > > Frankly because sn9c102 isn't very good code. In all fairness, none of > todays frameworks existed when sn9c102 was first created. It would be done > quite differently today. Note that AFAIK HdG has some of the webcams > supported by both gspca and sn9c102, I'm assuming those are working fine > with gspca. > > In my opinion the fact that the module has been removed from Fedora does > > not imply that the driver is unused. For sure that does not mean the > > sn9c102 driver is unuseful, since gspca does not work properly with all > > the devices, as I mentioned. > > The fact that nobody has been complaining about the removal from Fedora > indicates that very few people still use the webcams supported by sn9c102. > > That in itself is not a problem, but the fact that the code is really old > and needs a lot of work is. Within 1-2 years I am going to require that all > V4L2 drivers use at least some of the core frameworks in order to enforce > consistent API behavior. sn9c102 is one of the very few drivers that has > the unlucky combination of being too complex to easily/quickly convert, is > only rarely used, and for which there is a cheap and easy upgrade path for > the few remaining users (if any) of that driver (i.e. buy a uvc webcam). > > We have removed drivers in the past as well for similar reasons. It's done > very rarely: only if they start blocking progress, there is nobody > motivated to convert them, and they are only rarely (if ever) used. > > Regards, > > Hans -- To unsubscribe from this list: send the line "unsubscribe linux-media" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
