From: Srinivas Kandagatla srini@kernel.org
[ Upstream commit 8167f4f42572818fa8153be2b03e4c2120846603 ]
Qcom lpass is using component->id to keep DAI ID (A).
(S) static int lpass_platform_pcmops_open( sruct snd_soc_component *component, struct snd_pcm_substream *substream) { ^^^^^^^^^(B0) ... (B1) struct snd_soc_pcm_runtime *soc_runtime = snd_soc_substream_to_rtd(substream); (B2) struct snd_soc_dai *cpu_dai = snd_soc_rtd_to_cpu(soc_runtime, 0); ... (B3) unsigned int dai_id = cpu_dai->driver->id;
(A) component->id = dai_id; ... }
This driver can get dai_id from substream (B0 - B3). In this driver, below functions get dai_id from component->id (A).
(X) lpass_platform_pcmops_suspend() (Y) lpass_platform_pcmops_resume() (Z) lpass_platform_copy()
Here, (Z) can get it from substream (B0 - B3), don't need to use component->id (A). On suspend/resume (X)(Y), dai_id can only be obtained from component->id (A), because there is no substream (B0) in function parameter.
But, component->id (A) itself should not be used for such purpose. It is intilialized at snd_soc_component_initialize(), and parsed its ID (= component->id) from device name (a).
int snd_soc_component_initialize(...) { ... if (!component->name) { (a) component->name = fmt_single_name(dev, &component->id); ... ^^^^^^^^^^^^^ } ... }
Unfortunately, current code is broken to start with.
There are many regmaps that the driver cares about, however its only managing one (either dp or i2s) in component suspend/resume path.
I2S regmap is mandatory however other regmaps are setup based on flags like "hdmi_port_enable" and "codec_dma_enable".
Correct thing for suspend/resume path to handle is by checking these flags, instead of using component->id.
Signed-off-by: Srinivas Kandagatla srini@kernel.org Suggested-by: Kuninori Morimoto kuninori.morimoto.gx@renesas.com Signed-off-by: Kuninori Morimoto kuninori.morimoto.gx@renesas.com Link: https://patch.msgid.link/87a56ouuob.wl-kuninori.morimoto.gx@renesas.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org ---
LLM Generated explanations, may be completely bogus:
**YES**
This commit should be backported to stable kernel trees for the following reasons:
**1. Fixes a Real Bug with User Impact:** - The driver was misusing `component->id` to store DAI ID information, overwriting the ASoC framework's intended use of this field - This caused incomplete suspend/resume handling - only one regmap (either HDMI or I2S) was being handled instead of both when needed - Users would experience audio failures after suspend/resume cycles, especially on systems with both HDMI and I2S audio interfaces
**2. Clear Architectural Violation Being Fixed:** The commit message and code analysis show that `component->id` is initialized by the ASoC framework during `snd_soc_component_initialize()` based on device name parsing. The driver was incorrectly overwriting this value with DAI ID, breaking the abstraction layer between driver and framework.
**3. Limited Scope and Low Risk:** - Changes are confined to 3 functions in a single file (`lpass- platform.c`) - The fix replaces the problematic `component->id` usage with proper flag checking (`drvdata->hdmi_port_enable`) - No API changes or new features added - The author (Srinivas Kandagatla) is an experienced ASoC maintainer
**4. Improves Suspend/Resume Reliability:** The fix ensures both HDMI and I2S regmaps are properly handled during suspend/resume based on actual driver capabilities rather than an incorrectly stored ID. This makes power management more robust and predictable.
**5. Long-Standing Issue:** The problematic code has existed since late 2020 (commits b1824968221c and 8d1bfc04c974), affecting multiple kernel versions and potentially many Qualcomm-based devices in the field.
**Backport Recommendation:** Should be backported to all stable kernels from 5.10 onwards that contain the original problematic commits. This is a medium-high priority fix that improves audio subsystem reliability without introducing new risks.
sound/soc/qcom/lpass-platform.c | 27 +++++++++++++++++---------- 1 file changed, 17 insertions(+), 10 deletions(-)
diff --git a/sound/soc/qcom/lpass-platform.c b/sound/soc/qcom/lpass-platform.c index 9946f12254b3..b456e096f138 100644 --- a/sound/soc/qcom/lpass-platform.c +++ b/sound/soc/qcom/lpass-platform.c @@ -202,7 +202,6 @@ static int lpass_platform_pcmops_open(struct snd_soc_component *component, struct regmap *map; unsigned int dai_id = cpu_dai->driver->id;
- component->id = dai_id; data = kzalloc(sizeof(*data), GFP_KERNEL); if (!data) return -ENOMEM; @@ -1190,13 +1189,14 @@ static int lpass_platform_pcmops_suspend(struct snd_soc_component *component) { struct lpass_data *drvdata = snd_soc_component_get_drvdata(component); struct regmap *map; - unsigned int dai_id = component->id;
- if (dai_id == LPASS_DP_RX) + if (drvdata->hdmi_port_enable) { map = drvdata->hdmiif_map; - else - map = drvdata->lpaif_map; + regcache_cache_only(map, true); + regcache_mark_dirty(map); + }
+ map = drvdata->lpaif_map; regcache_cache_only(map, true); regcache_mark_dirty(map);
@@ -1207,14 +1207,19 @@ static int lpass_platform_pcmops_resume(struct snd_soc_component *component) { struct lpass_data *drvdata = snd_soc_component_get_drvdata(component); struct regmap *map; - unsigned int dai_id = component->id; + int ret;
- if (dai_id == LPASS_DP_RX) + if (drvdata->hdmi_port_enable) { map = drvdata->hdmiif_map; - else - map = drvdata->lpaif_map; + regcache_cache_only(map, false); + ret = regcache_sync(map); + if (ret) + return ret; + }
+ map = drvdata->lpaif_map; regcache_cache_only(map, false); + return regcache_sync(map); }
@@ -1224,7 +1229,9 @@ static int lpass_platform_copy(struct snd_soc_component *component, unsigned long bytes) { struct snd_pcm_runtime *rt = substream->runtime; - unsigned int dai_id = component->id; + struct snd_soc_pcm_runtime *soc_runtime = snd_soc_substream_to_rtd(substream); + struct snd_soc_dai *cpu_dai = snd_soc_rtd_to_cpu(soc_runtime, 0); + unsigned int dai_id = cpu_dai->driver->id; int ret = 0;
void __iomem *dma_buf = (void __iomem *) (rt->dma_area + pos +