2018-07-27 08:56:39

by Jia-Ju Bai

Subject: [PATCH] sound: usb: quirks: Replace mdelay() with msleep() and usleep_range()

snd_usb_select_mode_quirk(), snd_usb_set_interface_quirk() and
snd_usb_ctl_msg_quirk() are never called in atomic context.
They call mdelay() to busily wait, which is not necessary.
mdelay() can be replaced with msleep() and usleep_range().

This is found by a static analysis tool named DCNS written by myself.

Signed-off-by: Jia-Ju Bai <[email protected]>
---
sound/usb/quirks.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/sound/usb/quirks.c b/sound/usb/quirks.c
index acbeb52f6fd6..9eed650c54d4 100644
--- a/sound/usb/quirks.c
+++ b/sound/usb/quirks.c
@@ -1181,7 +1181,7 @@ int snd_usb_select_mode_quirk(struct snd_usb_substream *subs,
if (err < 0)
return err;

- mdelay(20); /* Delay needed after setting the interface */
+ msleep(20); /* Delay needed after setting the interface */

/* Vendor mode switch cmd is required. */
if (fmt->formats & SNDRV_PCM_FMTBIT_DSD_U32_BE) {
@@ -1202,7 +1202,7 @@ int snd_usb_select_mode_quirk(struct snd_usb_substream *subs,
return err;

}
- mdelay(20);
+ msleep(20);
}
return 0;
}
@@ -1249,7 +1249,7 @@ void snd_usb_set_interface_quirk(struct usb_device *dev)
switch (USB_ID_VENDOR(chip->usb_id)) {
case 0x23ba: /* Playback Design */
case 0x0644: /* TEAC Corp. */
- mdelay(50);
+ msleep(50);
break;
}
}
@@ -1269,7 +1269,7 @@ void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
*/
if (USB_ID_VENDOR(chip->usb_id) == 0x23ba &&
(requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
- mdelay(20);
+ msleep(20);

/*
* "TEAC Corp." products need a 20ms delay after each
@@ -1277,14 +1277,14 @@ void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
*/
if (USB_ID_VENDOR(chip->usb_id) == 0x0644 &&
(requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
- mdelay(20);
+ msleep(20);

/* ITF-USB DSD based DACs functionality need a delay
* after each class compliant request
*/
if (is_itf_usb_dsd_dac(chip->usb_id)
&& (requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
- mdelay(20);
+ msleep(20);

/* Zoom R16/24, Logitech H650e, Jabra 550a needs a tiny delay here,
* otherwise requests like get/set frequency return as failed despite
@@ -1294,7 +1294,7 @@ void snd_usb_ctl_msg_quirk(struct usb_device *dev, unsigned int pipe,
chip->usb_id == USB_ID(0x046d, 0x0a46) ||
chip->usb_id == USB_ID(0x0b0e, 0x0349)) &&
(requesttype & USB_TYPE_MASK) == USB_TYPE_CLASS)
- mdelay(1);
+ usleep_range(1000, 2000);
}

/*
--
2.17.0

2018-07-27 09:50:37

by Takashi Iwai

Subject: Re: [PATCH] sound: usb: quirks: Replace mdelay() with msleep() and usleep_range()

On Fri, 27 Jul 2018 10:55:28 +0200,
Jia-Ju Bai wrote:
>
> snd_usb_select_mode_quirk(), snd_usb_set_interface_quirk() and
> snd_usb_ctl_msg_quirk() are never called in atomic context.
> They call mdelay() to busily wait, which is not necessary.
> mdelay() can be replaced with msleep() and usleep_range().
>
> This is found by a static analysis tool named DCNS written by myself.
>
> Signed-off-by: Jia-Ju Bai <[email protected]>

Applied, thanks.


Takashi