At Wed, 28 Jun 2006 15:19:26 +0200 (CEST), Jaroslav Kysela wrote: > > On Wed, 28 Jun 2006, Takashi Iwai wrote: > > > > Yes, but that's the way how user control elements works. > > > > No, the question is how to pass the TLV list. Using the same ioctl > > for completely different purposes is confusing. > > Note that writting new TLV value / contents might make perfect sense, so > it's not completely wrong. Remember that TLV_WRITE is designed for a generic query. The caller can put an item to ask, and the driver is supposed to write the answer back. If the same mechanism is applied to the user-space elements, the queried item is simply registered as the new value and the whole previous TLVs are lost. (And even no error is returned!) > > > The similar > > > situation is for the element value where no "back to user space callback" > > > exists so the written values cannot be verified. > > > > Sorry what do you mean? The elements without tlv write support? > > In that case, you can know the TLV-WRITE ioctl is invalid for that > > element beforehand. > > No, I mean standard snd_ctl_elem_write() ioctl. There is no way to verify > if passed value is ok (no communication with the user space - the creator > task might not even exist, simply blind memcpy). It's fine because snd_ctl_eme_read() and snd_ctl_elem_write() are really corresponding 1:1. The write is just write, and the read is just read. But, TLV_WRITE is used for a query. The write means also read. It's the difference. > > > If you want the "correct" behaviour, an another layer must be designed > > > and we may call these elements as user-defined version 2. > > > > Urgh, it's a bad strategy to assume the next version before implementing > > the first version. > > Nope in my eyes, this implementation is far easier. Why bother with much > difficult stuff like the value update request queueing now? The important thing regarding desiging API is to define the demands from the application side. I feel it's still not well done. If we really need something, it must be implemented. If not needed, then we shouldn't implement it at all. Such a thing can be decided at the very first stage. Takashi Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
