Hi Per, On Thu, Sep 11, 2025 at 3:56 PM Per Waago (pwaago) <pwaago@xxxxxxxxx> wrote: > > > > > > ________________________________________ > > From: Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx> > > Sent: Thursday, September 11, 2025 17:52 > > To: Per Waago (pwaago) > > Cc: Pauli Virtanen; linux-bluetooth@xxxxxxxxxxxxxxx > > Subject: Re: [PATCH BlueZ] audio: Add support for specific error codes for A2DP configuration > > > > Hi Per, > > > > On Thu, Sep 11, 2025 at 11:12 AM Per Waago (pwaago) <pwaago@xxxxxxxxx> wrote: > > > > > > Hi Luiz, thanks for reviewing. > > > > > > > From: Luiz Augusto von Dentz <luiz.dentz@xxxxxxxxx> > > > > Sent: Thursday, September 11, 2025 16:43 > > > > To: Per Waago (pwaago); Pauli Virtanen > > > > Cc: linux-bluetooth@xxxxxxxxxxxxxxx > > > > Subject: Re: [PATCH BlueZ] audio: Add support for specific error codes for A2DP > configuration > > > > > > > > Hi Per, > > > > > > > > On Thu, Sep 11, 2025 at 9:56 AM Per Waagø <pwaago@xxxxxxxxx> wrote: > > > > > > > > > > The A2DP specification defines error codes that shall be used if > > > > > the codec capabilities contain improper settings. This change allows > > > > > clients to trigger the sending of these specific error codes by > > > > > returning the corresponding error messages from > > > > > MediaEndpoint1.SetConfiguration. > > > > > > > > > > This update is fully backwards compatible: clients passing other error > > > > > messages will continue to receive the default error code as before. On > > > > > older BlueZ versions, these new errors will also result in the default > > > > > error code, enabling clients to implement support for the new errors > > > > > without breaking compatibility. > > > > > > > > While I can see the value for debugging I doubt we could do any > > > > handling of these errors, so the result would be the same regardless > > > > of what error is sent back it is not recoverable. > > > > > > > > > > The main motivation for adding them is to be able to pass the > > > mandatory qualification tests, which now checks the errors codes > > > returned from SetConfiguration in detail. I don't think they are very > > > useful otherwise. > > > > > > The errors are specified in table 5.5 in the A2DP spec: > > > > https://www.bluetooth.com/specifications/specs/html/?src=a2dp_v1-4-1_1752513648/A2DP_v1.4.1/o> ut/en/index-en.html#UUID-0ba19ee9-7277-1068-d2dc-b9e638cca568_Table_5.5 > > > > > > I included all of them for completeness. In that table, it is also stated > > > which codecs they apply to. Some are SBC-specific, some apply to all codecs or > > > other codecs. > > > > Ok this is very annoying if PTS suddenly adds a new test case that > > checks error codes that otherwise are only useful for debugging. I'd > > say that it probably needs a configuration entry to skip these tests, > > btw this seems to be introduced in 1.4.1: > > > > https://www.bluetooth.com/specifications/specs/html/?src=a2dp_v1-4-1_1752513648/A2DP_v1.4.1/o> ut/en/index-en.html#UUID-05a1c924-2070-eb38-c2cc-a9ffa178bdb9 > > > > BlueZ SDP record is still 1.4 (a2dp_ver = 0x0104), it seems 1.4.1 is > > an errata only change but that introduces new error codes which is > > really intrusive to say the least.really intrusive to say the least. > > I have tried to read the specs in some more detail now. It seems the error > codes themselves have been there all the time. The errata that was incorporated > in 1.4.1 actually eases the requirements a bit, so the spec now says > that these error codes shall be returned if error codes from GAVDP or AVDTP > aren't used. So the way I interpret it, returning AVDTP_UNSUPPORTED_CONFIGURAION > could be ok according to 1.4.1. Indeed it says 'are not rejected with error codes specified by GAVDTP or AVDTP: 'If the Codec Specific Information Elements include improper settings and are not rejected with the error codes specified by GAVDP [3] or AVDTP [4], then an applicable error code from the list in Table 5.5 shall be returned.' So why it was failing if we returned AVDTP_UNSUPPORTED_CONFIGURATION, that should still be valid according to the above AVDTP error codes are still valid. -- Luiz Augusto von Dentz
