Markus, Em Ter, 2007-08-14 às 16:31 +0200, Markus Rechberger escreveu:> Following patch adds the possibility to implement tuner drivers in > userspace. As you asked me about userspace driver, at Linux Conf Europe, let megive you my feedback about it. On Linux, userspace-to-kernelspace APIs are meant to be forever. Thismeans that, once a newer API is created, this should remain supportedfor all future versions. So, such APIs should be carefully analyzed andaccepted by the community, before going to mainstream. I don't see any technical reason why tuner drivers should be moved touserspace. Looking at xc3028 device, the driver is very simple anddoesn't require any special treatment that it isn't possible to be doneat kernel. There are already some implementations on kernelspace thatworks fine. On the other hand, a TV driver without a tuner is a broken driver. Withparts of the driver being at userspace, this means to add undesiredcomplexity at the drivers architecture, while not bringing any benefit. If you look at V4L history, the first drivers started at userspace,being migrated to kernelspace, where we have the proper scenario formanaging those devices. Another aspect that should be analyzed is what is desired by thecommunity: kernelspace tuners or userspace tuners. Keeping support forboth at long term doesn't seem reasonable. The Linux community shoulddecide what is the better way. Currently, only you are pushing foruserspace tuners, mainly due to non-technical reasons. Almost all theother developers are comfortable with kernelspace tuners. So, creatingan userspace interface just to make you happy is not the way we shouldgo. A final aspect is that having an userspace driver for tuner will meanthat the kernel driver will depend on an userspace counterpart in orderto work. This will allow a vendor with bad intentions to release apartially broken userspace driver, with limited capabilities, and aclosed source driver for full support. This model is likely to occur, ifyou take a look at the past. For example: ATI and Nvidia closed sourcedrivers, several soft modem drivers, some network drivers, ... With all those issues, I'm against to add an userspace interface fortuners. Cheers,Mauro _______________________________________________linux-dvb mailing listlinux-dvb@xxxxxxxxxxxxxxx://www.linuxtv.org/cgi-bin/mailman/listinfo/linux-dvb
