Re: [PATCH] usb: gadget: u_audio.c: Adding Playback Pitch ctl for sync playback

[Greg KH <gregkh@linuxfoundation.org>]

On Wed, Oct 06, 2021 at 09:40:51AM +0200, Pavel Hofman wrote:
> 
> 
> Dne 06. 10. 21 v 9:34 Greg KH napsal(a):
> > On Wed, Oct 06, 2021 at 08:43:08AM +0200, Pavel Hofman wrote:
> > > 
> > > Dne 05. 10. 21 v 13:31 Greg KH napsal(a):
> > > > On Sat, Sep 25, 2021 at 04:30:03PM +0200, Pavel Hofman wrote:
> > > > > EP IN is hard-coded as ASYNC both in f_uac1 and f_uac2 but u_audio sends
> > > > > steady number of audio frames in each USB packet, without any control.
> > > > > 
> > > > > This patch adds 'Playback Pitch 1000000' ctl analogous to the existing
> > > > > 'Capture Pitch 1000000' ctl. The calculation of playback req->length in
> > > > > u_audio_iso_complete respects the Playback Pitch ctl value to 1ppm now.
> > > > > 
> > > > > Max. value for Playback Pitch is configured by the existing parameter
> > > > > uac2_opts->fb_max, used also for the Capture Pitch.
> > > > > 
> > > > > Since the EP IN packet size can be increased by uac2_opts->fb_max now,
> > > > > maxPacketSize for the playback direction is calculated by the same
> > > > > algorithm as for the async capture direction in
> > > > > f_uac2.c:set_ep_max_packet_size.
> > > > > 
> > > > > Signed-off-by: Pavel Hofman <pavel.hofman@ivitera.com>
> > > > > ---
> > > > >    drivers/usb/gadget/function/f_uac2.c  |  5 +-
> > > > >    drivers/usb/gadget/function/u_audio.c | 93 ++++++++++++++++++++-------
> > > > >    2 files changed, 74 insertions(+), 24 deletions(-)
> > > > 
> > > > Does not apply to my tree, what kernel release / branch did you make
> > > > this against?
> > > > 
> > > 
> > > Greg, the patch requires patch 0560c9c ("usb: gadget: f_uac2: fixed EP-IN
> > > wMaxPacketSize") which I sent prior to this one (not as a patch series, this
> > > patch was not ready at that time). You applied 0560c9c to your usb-linus
> > > yesterday, hence this patch applies cleanly to usb-linus now.
> > > 
> > > Your branch usb-next does not have 0560c9c yet, therefore the patch fails.
> > > But both patches apply cleanly to usb-next as a series, tested just now.
> > > 
> > > This patch ("usb: gadget: u_audio.c: Adding Playback Pitch ctl for sync
> > > playback") is not a bugfix and can wait in usb-next.
> > > 
> > > That goes back to my question of what are the rules for the two of your
> > > branches. What if a new patch requires patches from both usb-linus (bugfix)
> > > and usb-next (new features)?
> > 
> > I have 2 branches (well 3) in my tree:
> > 	master - tracks Linus's tree
> > 	usb-linus - patches to go to Linus for "this" release
> > 	usb-next - patches to go to Linus for the "next" release
> > 
> > 
> > So bugfixes go into usb-linus, and new features go into usb-next.
> > 
> > After the patches in usb-linus get merged into Linus, I merge that
> > branch (well Linus's -rc release) into the usb-next branch so that
> > dependencies can get resolved and bugfixes show up for testing.
> 
> Greg, thanks for the explanation. Very useful.
> 
> > 
> > or tell me and I will wait until that happens myself.
> 
> Is there a standardized way for that, e.g. somewhere in the PATCH mail
> message?

Put notes below the --- line and I will read them :)

thanks,

greg k-h