forked from unom/punktfunk
enricobuehlerandClaude Opus 5
ab88a8fb40
A wired DualSense on Fedora 44 / Bazzite / Arch presents exactly one playback
sink: the 1-channel `…Default__Speaker__sink`. GE-Proton mints its synthetic
"Sony controller speaker" endpoint from that lone mono sink, and Marvel's
Spider-Man Remastered overruns it — reliably, ~74 s in:
73.846 render_GetBuffer (…)->(5034, …) <- GE's mono endpoint
73.846 EXCEPTION_ACCESS_VIOLATION info[0]=1 (WRITE) info[1]=5CB9A000
Not a format mismatch: `GetMixFormat` and the game's `Initialize` both agree on
mono float32 `nBlockAlign 4`, and pulse sized `maxlength: 20136` = 5034 x 4
correctly. At the fault `rsi=rbp=0x13aa` (5034, the frame count) while
`rcx`/`rdx` are 5206/5207 — the copy loop had already run past the count. It is
a game/GE bug on a code path that ONLY EXISTS WHEN THE MONO SINK DOES.
So delete the mono sink rather than chase the overrun. `alsa-ucm-conf` describes
the pad as Speaker / Headphones / Mic / Headset and has never carried a
`SpeakerHaptic` device — the DualSense profile arrived upstream in 1.2.15
(36a111a) already without it, and the Deck's is a Valve downstream patch they
still carry on their own 1.2.16.1. With `SpeakerHaptic` at `PlaybackPriority
200` against `Speaker`'s 100 the card takes `HiFi (Mic, SpeakerHaptic)`, the
sink is the 4-channel one, and the mono sink — with the crash path — never
exists. The voice coils reach their own channels as a bonus.
Shipped WITHOUT replacing a file `alsa-ucm-conf` owns, which is what made this
awkward to package. `USB-Audio/USB-Audio.conf` ends with an unconditional,
optional include of `USB-Audio/conf.d/{vid}-{pid}.conf`, placed after its device
table has chosen `${var:ProfileName}` and before it includes the profile that
name resolves to — so a two-line drop-in keyed by 054c:0ce6 / 054c:0df2 swaps
the profile with no diversion, no `Conflicts`, and no `%config` fight. Verified
against alsa-lib rather than assumed: `ucm_cond.c` makes `Condition` optional
for a syntax-v8 `If` carrying `Append`, and `uc_mgr_evaluate_include` evaluates
each included subtree in place before moving to the next include, so the
`Define` lands before the profile include substitutes the variable. The hook and
the DualSense profile shipped in the SAME release (1.2.15), so every tree that
has the bug has the hook.
Host packages only (rpm — and therefore the Bazzite sysext, which unpacks the
RPMs — deb, Arch). The client already has a working fallback in
`ensure_pro_audio`, and a shared file in two co-installable packages is a file
conflict for a nicety. NixOS is not covered: it has no /usr/share/alsa/ucm2 to
drop into and needs a package override instead.
`scripts/ci/check-dualsense-ucm.sh` runs the whole chain on a real distro tree
with no hardware, via UCM's card-less `conf.virt.d` path with only the four card
built-ins stubbed. Against pristine Fedora 44 alsa-ucm-conf 1.2.16.1: baseline
`Headphones/Headset/Mic/Speaker`; with the drop-in, `SpeakerHaptic` and
`HeadphonesHaptic` too, `PlaybackPriority/SpeakerHaptic=200` over `Speaker`'s
100, `PlaybackPCM/SpeakerHaptic=…dualsense_haptic_out:…,1,1,2,3`. It exists
because this fix hooks another project's dispatcher: an upstream rename would
neuter it silently, and what comes back is the crash, not a quieter pad.
Negative-tested both ways (typo'd ProfileName, hook deleted).
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>