On Fri, May 27, 2022 at 06:13:38PM +0200, Takashi Iwai wrote:
On Wed, 25 May 2022 15:16:21 +0200, Vitaly Rodionov wrote: The idea to add / delete controls by the control element change doesn't sound good; as already mentioned in my reply to the previous patch set, the change of the control elements can be triggered too easily by any normal users who have the access to the sound devices. It means thousands of additions and removals per second could be attacked by any user.
This I am a little less sure how we handle. I mean arn't there already a few ways to do this? Both the existing ASoC wm_adsp stuff, and the topology stuff (used on all new Intel platforms, so very widely deployed) let you create controls by loading a firmware file. Also within ALSA itself can't user-space create user ALSA controls? Is there some rate limiting on that? How is this issue tackled there?
Moreover, the new controls with TLV controls don't look following the standard TLV syntax (type-length-value). My previous questions about the TLV usages are still unanswered, so I'm not sure what impact this would have, though. At least, alsactl behavior must be checked beforehand. If this is really device-specific (non-)TLV usages, it has to be clearly documented.
The TLV stuff should be completely removed once my latest comments have been updated. I don't think we need this for the amps and I would also rather keep the usage to a minimum until one of us finally gets around to resolving the large control issues in a way that is more acceptable to everyone (likely with a new IOCTL).
Thanks, Charles