[PATCH 0/3] ALSA: hda: Fix potential bad accesses at suspend/resume
Hi, this is a small patch series to address the bugs that triggers the unexpected accesses during the system suspend/resume. It happens often with Nvidia driver and HDMI codec driver, and it may lead to the serious CORB/RIRB errors. Although the issues are seen mostly on DP/HDMI, a part of the problems is rather generic to all platforms. Takashi === Takashi Iwai (3): ALSA: hda: Flush pending unsolicited events before suspend ALSA: hda: Avoid spurious unsol event handling during S3/S4 ALSA: hda/hdmi: Cancel pending works before suspend sound/pci/hda/hda_bind.c | 4 ++++ sound/pci/hda/hda_intel.c | 2 ++ sound/pci/hda/patch_hdmi.c | 13 +++++++++++++ 3 files changed, 19 insertions(+) -- 2.26.2
The HD-audio controller driver processes the unsolicited events via its work asynchronously, and this might be pending when the system goes to suspend. When a lengthy event handling like ELD byte reads is running, this might trigger unexpected accesses among suspend/resume procedure, typically seen with Nvidia driver that still requires the handling via unsolicited event verbs for ELD updates. This patch adds the flush of unsol_work to assure that pending events are processed before going into suspend. Buglink: https://bugzilla.suse.com/show_bug.cgi?id=1182377 Reported-and-tested-by: Abhishek Sahu <abhsahu@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de> --- sound/pci/hda/hda_intel.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/sound/pci/hda/hda_intel.c b/sound/pci/hda/hda_intel.c index 5b492c3f816c..5eea130dcf0a 100644 --- a/sound/pci/hda/hda_intel.c +++ b/sound/pci/hda/hda_intel.c @@ -1026,6 +1026,8 @@ static int azx_prepare(struct device *dev) chip = card->private_data; chip->pm_prepared = 1; + flush_work(&azx_bus(chip)->unsol_work); + /* HDA controller always requires different WAKEEN for runtime suspend * and system suspend, so don't use direct-complete here. */ -- 2.26.2
When HD-audio bus receives unsolicited events during its system suspend/resume (S3 and S4) phase, the controller driver may still try to process events although the codec chips are already (or yet) powered down. This might screw up the codec communication, resulting in CORB/RIRB errors. Such events should be rather skipped, as the codec chip status such as the jack status will be fully refreshed at the system resume time. Since we're tracking the system suspend/resume state in codec power.power_state field, let's add the check in the common unsol event handler entry point to filter out such events. BugLink: https://bugzilla.suse.com/show_bug.cgi?id=1182377 Tested-by: Abhishek Sahu <abhsahu@nvidia.com> Cc: <stable@vger.kernel.org> # 183ab39eb0ea: ALSA: hda: Initialize power_state Signed-off-by: Takashi Iwai <tiwai@suse.de> --- sound/pci/hda/hda_bind.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/sound/pci/hda/hda_bind.c b/sound/pci/hda/hda_bind.c index 6a8564566375..17a25e453f60 100644 --- a/sound/pci/hda/hda_bind.c +++ b/sound/pci/hda/hda_bind.c @@ -47,6 +47,10 @@ static void hda_codec_unsol_event(struct hdac_device *dev, unsigned int ev) if (codec->bus->shutdown) return; + /* ignore unsol events during system suspend/resume */ + if (codec->core.dev.power.power_state.event != PM_EVENT_ON) + return; + if (codec->patch_ops.unsol_event) codec->patch_ops.unsol_event(codec, ev); } -- 2.26.2
The per_pin->work might be still floating at the suspend, and this may hit the access to the hardware at an unexpected timing. Cancel the work properly at the suspend callback for avoiding the buggy access. Note that the bug doesn't trigger easily in the recent kernels since the work is queued only when the repoll count is set, and usually it's only at the resume callback, but it's still possible to hit in theory. BugLink: https://bugzilla.suse.com/show_bug.cgi?id=1182377 Reported-and-tested-by: Abhishek Sahu <abhsahu@nvidia.com> Cc: <stable@vger.kernel.org> Signed-off-by: Takashi Iwai <tiwai@suse.de> --- sound/pci/hda/patch_hdmi.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/sound/pci/hda/patch_hdmi.c b/sound/pci/hda/patch_hdmi.c index e6d0843ee9df..45ae845e82df 100644 --- a/sound/pci/hda/patch_hdmi.c +++ b/sound/pci/hda/patch_hdmi.c @@ -2480,6 +2480,18 @@ static void generic_hdmi_free(struct hda_codec *codec) } #ifdef CONFIG_PM +static int generic_hdmi_suspend(struct hda_codec *codec) +{ + struct hdmi_spec *spec = codec->spec; + int pin_idx; + + for (pin_idx = 0; pin_idx < spec->num_pins; pin_idx++) { + struct hdmi_spec_per_pin *per_pin = get_pin(spec, pin_idx); + cancel_delayed_work_sync(&per_pin->work); + } + return 0; +} + static int generic_hdmi_resume(struct hda_codec *codec) { struct hdmi_spec *spec = codec->spec; @@ -2503,6 +2515,7 @@ static const struct hda_codec_ops generic_hdmi_patch_ops = { .build_controls = generic_hdmi_build_controls, .unsol_event = hdmi_unsol_event, #ifdef CONFIG_PM + .suspend = generic_hdmi_suspend, .resume = generic_hdmi_resume, #endif }; -- 2.26.2
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Takashi Iwai