From: Mark Brown broonie@kernel.org
[ Upstream commit c4ca928a6db1593802cd945f075a7e21dd0430c1 ]
We currently log parse failures for ELD data and some disconnection events as errors without rate limiting. These log messages can be triggered very frequently in some situations, especially ELD parsing when there is nothing connected to a HDMI port which will generate:
hdmi-audio-codec hdmi-audio-codec.1.auto: HDMI: Unknown ELD version 0
While there's doubtless work that could be done on reducing the number of connection notification callbacks it's possible these may be legitimately generated by poor quality physical connections so let's use rate limiting to mitigate the log spam for the parse errors and lower the severity for disconnect logging to debug level.
Signed-off-by: Mark Brown broonie@kernel.org Link: https://patch.msgid.link/20250613-asoc-hdmi-eld-logging-v1-1-76d64154d969@ke... Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org ---
LLM Generated explanations, may be completely bogus:
**Backport Status: YES**
This commit is a good candidate for backporting to stable kernel trees for the following reasons:
1. **Fixes a real user-facing bug**: The commit addresses log spam issues that can fill system logs with repeated error messages. When no HDMI display is connected, the driver continuously logs "HDMI: Unknown ELD version 0" errors, which can consume disk space and make logs difficult to analyze.
2. **Small and contained fix**: The changes are minimal and focused: - Changes `dev_err()` to `dev_err_ratelimited()` in two locations within `hdac_hdmi_parse_eld()` (lines 1233-1234 and 1242-1243) - Changes `dev_err()` to `dev_dbg()` for disconnect messages in `hdac_hdmi_present_sense()` (lines 1302-1303) - Total of just 3 logging statement modifications
3. **No functional changes**: The commit only modifies logging behavior without changing any driver logic, state management, or hardware interaction. This minimizes regression risk.
4. **Affects a common use case**: The issue occurs when HDMI ports are unconnected, which is a normal operating condition for many systems. Users may have HDMI ports they never use, or may frequently plug/unplug monitors.
5. **No architectural changes**: The fix doesn't introduce new features or modify the driver's architecture. It simply rate-limits existing error messages and downgrades one message's severity.
6. **Clear problem and solution**: The commit message clearly describes the issue (log spam from ELD parsing failures) and the straightforward solution (rate limiting and severity adjustment).
The specific code changes show: - In `hdac_hdmi_parse_eld()`: Rate-limiting prevents flooding logs when ELD data is invalid/unavailable - In `hdac_hdmi_present_sense()`: Downgrading disconnect messages from error to debug level is appropriate since disconnection is a normal event, not an error condition
This meets the stable kernel criteria of being a simple fix for an annoying bug that affects users without introducing new risks.
sound/soc/codecs/hdac_hdmi.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-)
diff --git a/sound/soc/codecs/hdac_hdmi.c b/sound/soc/codecs/hdac_hdmi.c index 1acd82f81ba0..bafdaedbee86 100644 --- a/sound/soc/codecs/hdac_hdmi.c +++ b/sound/soc/codecs/hdac_hdmi.c @@ -1230,7 +1230,8 @@ static int hdac_hdmi_parse_eld(struct hdac_device *hdev, >> DRM_ELD_VER_SHIFT;
if (ver != ELD_VER_CEA_861D && ver != ELD_VER_PARTIAL) { - dev_err(&hdev->dev, "HDMI: Unknown ELD version %d\n", ver); + dev_err_ratelimited(&hdev->dev, + "HDMI: Unknown ELD version %d\n", ver); return -EINVAL; }
@@ -1238,7 +1239,8 @@ static int hdac_hdmi_parse_eld(struct hdac_device *hdev, DRM_ELD_MNL_MASK) >> DRM_ELD_MNL_SHIFT;
if (mnl > ELD_MAX_MNL) { - dev_err(&hdev->dev, "HDMI: MNL Invalid %d\n", mnl); + dev_err_ratelimited(&hdev->dev, + "HDMI: MNL Invalid %d\n", mnl); return -EINVAL; }
@@ -1297,8 +1299,8 @@ static void hdac_hdmi_present_sense(struct hdac_hdmi_pin *pin,
if (!port->eld.monitor_present || !port->eld.eld_valid) {
- dev_err(&hdev->dev, "%s: disconnect for pin:port %d:%d\n", - __func__, pin->nid, port->id); + dev_dbg(&hdev->dev, "%s: disconnect for pin:port %d:%d\n", + __func__, pin->nid, port->id);
/* * PCMs are not registered during device probe, so don't