Re: [PATCH v3] drm/i915/audio: treat UHBR SST like MST for cpu_transcoder signalling
Jani Nikula <[email protected]> Tue, 28 Jul 2026 11:59:53 +0300
| Newsgroups | org.freedesktop.lists.intel-gfx,org.freedesktop.lists.intel-xe |
|---|---|
| Organization | Intel Finland Oy - BIC 0357606-4 - c/o Alberga Business Park, 6 krs Bertel Jungin Aukio 5, 02600 Espoo, Finland |
| Message-ID | <[email protected]> |
On Wed, 08 Jul 2026, Mitul Golani <[email protected]> wrote: > Both DP MST and UHBR SST require the audio component to use a real > cpu_transcoder (>= 0) value to identify the audio stream on a port. > For DP MST this was already handled; for UHBR SST it was not, causing > pin_eld_notify() to signal cpu_transcoder = -1 (the legacy SST sentinel) > and find_audio_state() to skip the per-transcoder entry for the UHBR > stream. > > After suspend/resume or replug, the ELD lookup fails and audio goes > silent. Fix by detecting UHBR SST alongside DP MST when deciding > whether a real cpu_transcoder value must be used for audio state > addressing, in both the pin_eld_notify() signalling and the > find_audio_state() lookup paths. [snip] Going through some merged patches while writing the pull request... > > - /* Non-MST */ > + /* Legacy SST. */ Please be careful about tossing around "legacy". It's the bog standard DP 1.4 non-UHBR SST that's used absolutely everywere that you're talking about here. It's not "legacy". BR, Jani. -- Jani Nikula, Intel