Add additional check in hdmi_find_pcm_slot() to not return a pcm index that points to unallocated pcm. This could happen if codec driver is set up in codec->mst_no_extra_pcms mode. On some platforms, this leads to a kernel oops in snd_ctl_notify(), called via update_eld().
BugLink: https://github.com/thesofproject/linux/issues/1536 Fixes: 5398e94fb753 ALSA: hda - Add DP-MST support for NVIDIA codecs Signed-off-by: Kai Vehmanen kai.vehmanen@linux.intel.com --- sound/pci/hda/patch_hdmi.c | 22 +++++++++++----------- 1 file changed, 11 insertions(+), 11 deletions(-)
diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c index 373ca99b7a2f..c3940c197122 100644 --- a/sound/pci/hda/patch_hdmi.c +++ b/sound/pci/hda/patch_hdmi.c @@ -1335,24 +1335,24 @@ static int hdmi_find_pcm_slot(struct hdmi_spec *spec, int i;
/* - * generic_hdmi_build_pcms() allocates (num_nids + dev_num - 1) - * number of pcms. + * generic_hdmi_build_pcms() may allocate extra PCMs on some + * platforms (with maximum of 'num_nids + dev_num - 1') * * The per_pin of pin_nid_idx=n and dev_id=m prefers to get pcm-n * if m==0. This guarantees that dynamic pcm assignments are compatible - * with the legacy static per_pin-pmc assignment that existed in the + * with the legacy static per_pin-pcm assignment that existed in the * days before DP-MST. * * per_pin of m!=0 prefers to get pcm=(num_nids + (m - 1)). */ - if (per_pin->dev_id == 0 && - !test_bit(per_pin->pin_nid_idx, &spec->pcm_bitmap)) - return per_pin->pin_nid_idx; - - if (per_pin->dev_id != 0 && - !(test_bit(spec->num_nids + (per_pin->dev_id - 1), - &spec->pcm_bitmap))) { - return spec->num_nids + (per_pin->dev_id - 1); + + if (per_pin->dev_id == 0) { + if (!test_bit(per_pin->pin_nid_idx, &spec->pcm_bitmap)) + return per_pin->pin_nid_idx; + } else { + i = spec->num_nids + (per_pin->dev_id - 1); + if (i < spec->pcm_used && !(test_bit(i, &spec->pcm_bitmap))) + return i; }
/* have a second try; check the area over num_nids */