Re: Creative X-Fi hw20k2 (SB0880) that appeared in kernel 6.12.85

On Tue, 02 Jun 2026 13:32:42 +0200,
Cliff Brady wrote:
> 
> 
> Hi Takashi,
> 
> I'm writing to report a regression on the Creative X-Fi hw20k2 (SB0880) that
> appeared in kernel 6.12.85, and which I believe is related to commit
> b045ab3dff97 ("ALSA: ctxfi: Fix missing SPDIFI1 index handling").
> 
> Hardware:
>   Card: Creative X-Fi 20K2, model SB0880 (PCI ID 1102:000b)
>   Driver: snd_ctxfi
>   Kernel: 6.12.85 (Home Assistant OS 17.3, generic x86-64)
> 
> Symptom:
> After upgrading from HAOS 17.2 (kernel 6.12.77) to HAOS 17.3 (kernel 6.12.85),
> the X-Fi analog outputs produce no audio when accessed via PulseAudio.  HAOS
> 17.1 (kernel 6.12.67) X-Fi analog outputs also  successfully produced audio
> when accessed via PulseAudio  The PA sink reports RUNNING and all ALSA mixer
> controls are at full volume and unmuted, but no audio is heard from any analog
> output channel (front, rear, side, center/LFE).
> 
> Diagnosis:
> PA opens the device with device.access_mode = "mmap+timer". Direct ALSA access
> via speaker-test bypassing PA produces audio correctly on all channels.
> Forcing PA to close and reopen the PCM device via pactl suspend-sink /
> resume-sink restores audio, suggesting the mmap buffer handshake between PA
> and the ctxfi driver is failing silently on device open.
> 
> The issue is reproducible every time PA opens the device fresh (e.g. after pa
> restart or sink resume from suspended state following idle timeout). The
> suspend/resume workaround reliably restores audio each time.
> 
> Hypothesis:
> The out-of-bounds array access fixed by commit b045ab3dff97 in
> daio_device_index() for hw20k2 may have been inadvertently masking a
> pre-existing deficiency in the ctxfi mmap implementation. With the fix in
> place, mmap+timer mode is negotiated successfully at the PA/kernel interface
> but audio transfers silently fail. A possible fix would be to set
> SNDRV_PCM_INFO_NO_MMAP in the hw20k2 PCM capabilities, forcing PA to fall back
> to read/write mode which works correctly.
> 
> Kernel was working: 6.12.77
> Kernel regression introduced: 6.12.85
> 
> I am happy to test any patch or provide further diagnostics.

Could you check the latest 7.0.x kernel?  There are a few more fixes
for ctxfi recently.


Takashi