From: Cássio Gabriel Date: Mon, 18 May 2026 14:32:05 +0000 (-0300) Subject: ALSA: ice1724: Fix blocking open for independent surround PCMs X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1ab8e422dc779a91acba2d0aafc47b0db6680b4b;p=thirdparty%2Flinux.git ALSA: ice1724: Fix blocking open for independent surround PCMs The independent surround playback open path rejects a substream when the matching PDMA channel is reserved by the multi-channel PDMA0 stream. It currently returns -EBUSY for that case, although the driver has carried a FIXME noting that blocking mode is not handled properly. ALSA PCM open waits and retries only when the low-level open callback returns -EAGAIN. Returning -EBUSY therefore makes blocking opens fail immediately, the same as nonblocking opens. Return -EAGAIN for the temporary PDMA0 reservation conflict. The PCM core continues to report -EBUSY for O_NONBLOCK callers, while blocking callers sleep and retry. Also wake the independent surround PCM wait queue when hw_free releases a PDMA reservation. The reservation can be released by the pro PCM, while waiters are sleeping on the independent surround PCM, so waking the current substream PCM is not sufficient for this cross-PCM reservation. Signed-off-by: Cássio Gabriel Link: https://patch.msgid.link/20260518-ice1724-blocking-open-v1-1-1bfa3e5aa7cf@gmail.com Signed-off-by: Takashi Iwai --- diff --git a/sound/pci/ice1712/ice1724.c b/sound/pci/ice1712/ice1724.c index 2e64f9c020e5..79d57938a1c8 100644 --- a/sound/pci/ice1712/ice1724.c +++ b/sound/pci/ice1712/ice1724.c @@ -730,13 +730,22 @@ static int snd_vt1724_pcm_hw_params(struct snd_pcm_substream *substream, static int snd_vt1724_pcm_hw_free(struct snd_pcm_substream *substream) { struct snd_ice1712 *ice = snd_pcm_substream_chip(substream); + bool released = false; int i; - guard(mutex)(&ice->open_mutex); - /* unmark surround channels */ - for (i = 0; i < 3; i++) - if (ice->pcm_reserved[i] == substream) + scoped_guard(mutex, &ice->open_mutex) { + /* unmark surround channels */ + for (i = 0; i < 3; i++) { + if (ice->pcm_reserved[i] != substream) + continue; ice->pcm_reserved[i] = NULL; + released = true; + } + } + + if (released && ice->pcm_ds) + wake_up(&ice->pcm_ds->open_wait); + return 0; } @@ -1364,7 +1373,7 @@ static int snd_vt1724_playback_indep_open(struct snd_pcm_substream *substream) scoped_guard(mutex, &ice->open_mutex) { /* already used by PDMA0? */ if (ice->pcm_reserved[substream->number]) - return -EBUSY; /* FIXME: should handle blocking mode properly */ + return -EAGAIN; } runtime->private_data = (void *)&vt1724_playback_dma_regs[substream->number]; ice->playback_con_substream_ds[substream->number] = substream;