On 3/15/2011 12:29 PM, Luiz Augusto von Dentz wrote:
Hi,
On Tue, Mar 15, 2011 at 2:01 PM, Johan Hedberg<johan.hedberg@xxxxxxxxx> wrote:
Hi Arun,
On Tue, Mar 15, 2011, Arun Raghavan wrote:
I've been trying to set up PulseAudio to be able to switch the A2DP sink
dynamically between SBC and MPEG modes. I've got this working now [1], but I
did face one problem on the bluez side. When sending a reconfigure request, the
request always goes to the SEID that was used previously (=> always to the SBC
SEID). Trying to reconfigure for MPEG therefore results the headset returning
an error. I'm not very familiar with how this is supposed to work, but the
patch following this mail seems to work (I can now switch back and forth
between SBC and MPEG modes). It basically forces figuring out what remote SEP
to talk to while reconfiguring.
Is this the right approach?
I'm not sure about the places where you set the value to NULL, but the
place in close_cfm which you remove isn't acceptable as such. It was
originally created to fix the issue reported in this thread:
http://marc.info/?l=linux-bluetooth&m=129190286303247&w=2
Only a fix which doesn't break the use-case reported there can be
accepted upstream. FWIW, the commit that introduced the fix is de96fcd8.
Also the solution should consider a transition and not dropping the
stream completely before configuring the other, otherwise errors may
cause a complete disconnect just to switch between endpoints. Actually
I would suggest configuring both endpoint since the beginning so that
we only need to suspend/resume to switch between them, but I don't
think many headsets would be able to handle this situation.
I think most headsets will not support this because it would require an
extra L2CAP connection to be maintained.
I don't think there is much of a big deal with closing the first
endpoint relationship prior to configuring the next, becuase the AVDTP
signaling channel will keep the underlying ACL connection open. Headsets
I have worked on in the past would reject a SET_CONFIG if an existing
local/remote SEID relationship already existed, not only for the extra
resources required to maintain the extra L2CAP channel, but also because
the SET_CONFIG is when the hw resources are reserved and configured for
the actual PCM data stream.
And assuming that the ACL doesn't get dropped, the critical re-setup
time is probably most bounded by the underlying hw reconfiguration, and
not so much by the few extra small ACL pkts that need to be exchanged.
--
Brian Gix
bgix@xxxxxxxxxxxxxx
Employee of Qualcomm Innovation Center, Inc.
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum
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