[PATCH 1/4] ALSA: usb-audio: qcom: Improve error logging in USB offload

[PATCH 1/4] ALSA: usb-audio: qcom: Improve error logging in USB offload

[wangdich9700]

From: wangdicheng <wangdicheng@kylinos.cn>

Add error codes to error messages for better debugging.
This helps identify the root cause when USB audio offload fails.

Error messages now include the actual error code returned by
xhci_sideband operations, making it easier to diagnose failures
during USB audio offload setup.

Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>
---
 sound/usb/qcom/qc_audio_offload.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c
index a0009503b2c5..f99f8bddb237 100644
--- a/sound/usb/qcom/qc_audio_offload.c
+++ b/sound/usb/qcom/qc_audio_offload.c
@@ -1140,7 +1140,7 @@ uaudio_endpoint_setup(struct snd_usb_substream *subs,
 	ret = xhci_sideband_add_endpoint(uadev[card_num].sb, ep);
 	if (ret < 0) {
 		dev_err(&subs->dev->dev,
-			"failed to add data ep to sec intr\n");
+			"failed to add data ep to sec intr: %d\n", ret);
 		ret = -ENODEV;
 		goto exit;
 	}
@@ -1148,7 +1148,7 @@ uaudio_endpoint_setup(struct snd_usb_substream *subs,
 	sgt = xhci_sideband_get_endpoint_buffer(uadev[card_num].sb, ep);
 	if (!sgt) {
 		dev_err(&subs->dev->dev,
-			"failed to get data ep ring address\n");
+			"failed to get data ep ring address: %d\n", ret);
 		ret = -ENODEV;
 		goto remove_ep;
 	}
-- 
2.25.1

[PATCH 2/4] ALSA: usb-audio: qcom: Use snprintf for mixer control name formatting

[wangdich9700]

From: wangdicheng <wangdicheng@kylinos.cn>

The current code uses sprintf() to format control names without bounds
checking, which could lead to buffer overflow if PCM index is large.
Replace sprintf with snprintf to ensure buffer safety.

The ctl_name buffer is 48 bytes, and the formatted string could exceed
this with large PCM index values. Using snprintf with sizeof(ctl_name)
prevents potential buffer overflow.

Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>
---
 sound/usb/qcom/mixer_usb_offload.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/sound/usb/qcom/mixer_usb_offload.c b/sound/usb/qcom/mixer_usb_offload.c
index 2adeb64f4d33..48e55d5872d5 100644
--- a/sound/usb/qcom/mixer_usb_offload.c
+++ b/sound/usb/qcom/mixer_usb_offload.c
@@ -128,7 +128,7 @@ int snd_usb_offload_create_ctl(struct snd_usb_audio *chip, struct device *bedev)
 		 */
 		chip_kctl->private_value = as->pcm_index |
 					  chip->card->number << 16;
-		sprintf(ctl_name, "USB Offload Playback Card Route PCM#%d",
+		snprintf(ctl_name, sizeof(ctl_name), "USB Offload Playback Card Route PCM#%d",
 			as->pcm_index);
 		chip_kctl->name = ctl_name;
 		ret = snd_ctl_add(chip->card, snd_ctl_new1(chip_kctl, bedev));
@@ -143,7 +143,7 @@ int snd_usb_offload_create_ctl(struct snd_usb_audio *chip, struct device *bedev)
 		 */
 		chip_kctl->private_value = as->pcm_index |
 					  chip->card->number << 16;
-		sprintf(ctl_name, "USB Offload Playback PCM Route PCM#%d",
+		snprintf(ctl_name, sizeof(ctl_name), "USB Offload Playback PCM Route PCM#%d",
 			as->pcm_index);
 		chip_kctl->name = ctl_name;
 		ret = snd_ctl_add(chip->card, snd_ctl_new1(chip_kctl, bedev));
-- 
2.25.1

[PATCH 3/4] ALSA: usb-audio: qcom: Fix return value in qc_usb_audio_offload_fill_avail_pcms

[wangdich9700]

From: wangdicheng <wangdicheng@kylinos.cn>

The function qc_usb_audio_offload_fill_avail_pcms() always returns -1
regardless of how many PCM devices were successfully filled. This makes
it impossible for callers to know the actual number of available PCMs.

Return the actual count of filled PCM devices instead, which allows
callers to verify that all expected PCMs were properly enumerated.

Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>
---
 sound/usb/qcom/qc_audio_offload.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c
index f99f8bddb237..fa7ee61d6934 100644
--- a/sound/usb/qcom/qc_audio_offload.c
+++ b/sound/usb/qcom/qc_audio_offload.c
@@ -1753,7 +1753,7 @@ static int qc_usb_audio_offload_fill_avail_pcms(struct snd_usb_audio *chip,
 			break;
 	}
 
-	return -1;
+	return idx;
 }
 
 /**
-- 
2.25.1

[PATCH 4/4] ALSA: usb-audio: qcom: Use PAGE_ALIGN macro for buffer size calculation

[wangdich9700]

From: wangdicheng <wangdicheng@kylinos.cn>

Use the kernel's PAGE_ALIGN() macro instead of open-coding the page
alignment calculation. This improves code readability and follows
kernel coding style.

The manual calculation:
  mult = len / PAGE_SIZE;
  remainder = len % PAGE_SIZE;
  len = mult * PAGE_SIZE;
  len += remainder ? PAGE_SIZE : 0;

is equivalent to:
  len = PAGE_ALIGN(len);

Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>
---
 sound/usb/qcom/qc_audio_offload.c | 5 +----
 1 file changed, 1 insertion(+), 4 deletions(-)

diff --git a/sound/usb/qcom/qc_audio_offload.c b/sound/usb/qcom/qc_audio_offload.c
index fa7ee61d6934..32982318fbed 100644
--- a/sound/usb/qcom/qc_audio_offload.c
+++ b/sound/usb/qcom/qc_audio_offload.c
@@ -1052,10 +1052,7 @@ static int uaudio_transfer_buffer_setup(struct snd_usb_substream *subs,
 	if (!len)
 		len = PAGE_SIZE;
 
-	mult = len / PAGE_SIZE;
-	remainder = len % PAGE_SIZE;
-	len = mult * PAGE_SIZE;
-	len += remainder ? PAGE_SIZE : 0;
+	len = PAGE_ALIGN(len);
 
 	if (len > MAX_XFER_BUFF_LEN) {
 		dev_err(uaudio_qdev->data->dev,
-- 
2.25.1

Re: [PATCH 1/4] ALSA: usb-audio: qcom: Improve error logging in USB offload

[Takashi Iwai]

On Wed, 03 Jun 2026 11:10:59 +0200,
wangdich9700@163.com wrote:
> 
> From: wangdicheng <wangdicheng@kylinos.cn>
> 
> Add error codes to error messages for better debugging.
> This helps identify the root cause when USB audio offload fails.
> 
> Error messages now include the actual error code returned by
> xhci_sideband operations, making it easier to diagnose failures
> during USB audio offload setup.
> 
> Signed-off-by: wangdicheng <wangdicheng@kylinos.cn>

Applied all four patches to for-next branch now.

But, at the next time, when there are a series of patches, please give
a cover letter to understand better the big picture.


thanks,

Takashi