From: Clemens Ladisch clemens@ladisch.de
Ivan Bublikov wrote:
As an HDA codec vendor, I want to be able to control some functionality in my codec, that is not present in codecs from other vendors. [...] I can register an IOCTL handler using snd_ctl_register_ioctl.
This functions is for ioctl calls on the ctl device, which is global for one sound card and is not appropriate if one wants to address something like a PCM device or a codec.
For a HDA codec, use a hwdep device.
OK, I understand I simply need to add a new case in hda_hwdep_ioctl().
My difficulty is how to define a code for my IOCTL and avoid a conflict with the common code in the future.
Pick something not yet allocated in Documentation/ioctl/ioctl-number.txt.
Since half of the lines in it are marked "Conflict!" anyway, should I only pay attention to not conflict with "sound/*" lines? And then add a new line for my IOCTLs? And should I put my IOCTL definitions in hda_hwdep.h or create a new file?