At Fri, 04 Oct 2002 11:04:23 -0700, Florian Bomers wrote: > > Jaroslav Kysela wrote: > > > > On Thu, 3 Oct 2002, Florian Bomers wrote: > > > > > Hi, > > > > > > there is snd_pcm_sw_params_current() but not snd_pcm_hw_params_current(). How > > > can I get the current hardware configuration for a given snd_pcm_t handle ? Am I > > > missing something ? > > > > Hardware parameters must be configured from application all time. > > So that means that I need to cache hw params if I ever want to use them again ? > E.g. my app does this: > > open(), set hw params, set sw params > free hw params and sw params to save memory > > work with the device: start/write/stop/etc. > > When I now want to know the buffer size, I would like to obtain the current hw > params which I had set above to the pcm handle. > > I understand that I initially need to set hw params to a pcm handle before I > could get current hw params, but once I did that, especially in prepared/running > state, the device has well-defined hw params and why shouldn't people be allowed > to query them ?
simply because the query function is not implemented on the kernel side :) or, we can add the code to alsa-lib to duplicate the hw_params / sw_params privately, and returns it via the query function. but it's not much different fromt keeping hw_params or sw_params record in the application by yourself. please note that on the kernel, hw_params and sw_params are not stored as they are but their members are copied to runtime struct. so if the query api is implemented, we need a function to convert from runtime to hw_params or sw_params. Takashi ------------------------------------------------------- This sf.net email is sponsored by:ThinkGeek Welcome to geek heaven. http://thinkgeek.com/sf _______________________________________________ Alsa-devel mailing list [EMAIL PROTECTED] https://lists.sourceforge.net/lists/listinfo/alsa-devel
