On Thu, Feb 17, 2022 at 09:42:00AM +0800, Jing Leng wrote: > Hi Greg KH, > > > So is this a bug in the Host side to not do stuff like this? Why not > > fix it there instead? > > > > Where is the requirement that this command must be handled by the > > device? > > > > First we need to clarify two issues. > > 1. Does the Ubuntu go beyond the UAC1 specification? > No. > On page 66 of the UAC1 specification ( > https://www.usb.org/sites/default/files/audio10.pdf): > The bRequest can be SET_CUR, SET_MIN, SET_MAX, SET_RES or SET_MEM. > In most cases, only the CUR and MEM attribute will be supported for > the Set request. However, this specification does not prevent a > designer from making other attributes programmable. > Supplement: Windows 10 only sends SET_CUR request. > > 2. Does the old version kernel have the problem on the Ubuntu? > NO. (e.g. linux-5.10) > The problem is introduced by the following modification: > commit 0356e6283c7177391d144612f4b12986ed5c4f6e > Author: Ruslan Bilovol <ruslan.bilovol@xxxxxxxxx> > Date: Mon Jul 12 14:55:29 2021 +0200 > > usb: gadget: f_uac1: add volume and mute support Then please add this commit id as a "Fixes:" tag in the changelog area. thanks, greg k-h
