On Mon, 15 May 2017 16:29:47 +0200, Takashi Sakamoto wrote: > > On May 15 2017 17:42, Takashi Iwai wrote: > > On Sun, 14 May 2017 10:57:35 +0200, > > Takashi Sakamoto wrote: > >> > >> Hi, > >> > >> In the last Audio Mini Conference held with Linux Plumber conference 2016[1], I mentioned about tracepoints for PCM params operation. This patchset is for the idea. > >> > >> In ALSA PCM interface, applications can get hardware capability by ioctl(2) with SNDRV_PCM_IOCTL_HW_REFINE/SNDRV_PCM_IOCT_HW_PARAMS in a shape of 'struct snd_pcm_hw_params'. In kernel side, relevant processing is somewhat complicated and developers sometimes have hard time to debug drivers for PCM constraints and rules. > >> > >> This patchset adds tracepoints for hw_params operations. When CONFIG_SND_DEBUG is enabled, you can see 'trace_hw_params_mask/trace_hw_params_interval' events of 'snd_pcm' subsystem. When applications execute ioctl(2) with SNDRV_PCM_IOCTL_HW_REFINE/SNDRV_PCM_IOCTL_HW_PARAMS, these events are probed. Developers can get how many PCM rules are added into runtime of PCM substream and which rule changed which parameters. > >> > >> This patchset also includes some improvements. The last three commits brings small changes to kernel/userspace interface for error handling. > >> > >> I'm happy to receive your comment for this patchset. For your information, low level application of SNDRV_PCM_IOCTL_HW_REFINE operation is available in my github repository[2]. > > > > The patches look good through a quick glance. > > The only concern I have is the function regression, since there are > > lots of code rewrites. How did you test? > > Currently, I did four things: > > 1. understand logic to process parameters, constraints and rules > 2. add the tracepoints as early as the patchset > 3. confirm that probed events include the same data commit by commit > 4. do the above with refine-pcm-params.c and got valid results > > For the above, I use ALSA Fireweorks/OXFW driver and supported > devices, which I know correct behaviour. Maybe we can have some test set using dummy driver, too? Takashi _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
