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ALSA: line6: Return error if device not responding 

Put an upper bound on how long we will wait for the device to respond to
a read/write request (i.e., 100 milliseconds) and return an error if
this is reached.

Signed-off-by: Chris Rorvick <chris@rorvick.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
This commit is contained in:
Chris Rorvick 2015-02-10 23:03:14 -06:00 committed by Takashi Iwai
parent e64e94df99
commit f3dfd1be08
1 changed files with 23 additions and 6 deletions
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29
sound/usb/line6/driver.c
View File

@ -297,6 +297,7 @@ static void line6_data_received(struct urb *urb)
}
#define LINE6_READ_WRITE_STATUS_DELAY 2 /* milliseconds */
#define LINE6_READ_WRITE_MAX_RETRIES 50
/*
Read data from device.
@ -307,6 +308,7 @@ int line6_read_data(struct usb_line6 *line6, int address, void *data,
struct usb_device *usbdev = line6->usbdev;
int ret;
unsigned char len;
unsigned count;
/* query the serial number: */
ret = usb_control_msg(usbdev, usb_sndctrlpipe(usbdev, 0), 0x67,
@ -320,7 +322,7 @@ int line6_read_data(struct usb_line6 *line6, int address, void *data,
}
/* Wait for data length. We'll get 0xff until length arrives. */
do {
for (count = 0; count < LINE6_READ_WRITE_MAX_RETRIES; count++) {
mdelay(LINE6_READ_WRITE_STATUS_DELAY);
ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0), 0x67,
@ -333,9 +335,16 @@ int line6_read_data(struct usb_line6 *line6, int address, void *data,
"receive length failed (error %d)\n", ret);
return ret;
}
} while (len == 0xff);
if (len != datalen) {
if (len != 0xff)
break;
}
if (len == 0xff) {
dev_err(line6->ifcdev, "read failed after %d retries\n",
count);
return -EIO;
} else if (len != datalen) {
/* should be equal or something went wrong */
dev_err(line6->ifcdev,
"length mismatch (expected %d, got %d)\n",
@ -367,6 +376,7 @@ int line6_write_data(struct usb_line6 *line6, int address, void *data,
struct usb_device *usbdev = line6->usbdev;
int ret;
unsigned char status;
int count;
ret = usb_control_msg(usbdev, usb_sndctrlpipe(usbdev, 0), 0x67,
USB_TYPE_VENDOR | USB_RECIP_DEVICE | USB_DIR_OUT,
@ -379,7 +389,7 @@ int line6_write_data(struct usb_line6 *line6, int address, void *data,
return ret;
}
do {
for (count = 0; count < LINE6_READ_WRITE_MAX_RETRIES; count++) {
mdelay(LINE6_READ_WRITE_STATUS_DELAY);
ret = usb_control_msg(usbdev, usb_rcvctrlpipe(usbdev, 0),
@ -394,9 +404,16 @@ int line6_write_data(struct usb_line6 *line6, int address, void *data,
"receiving status failed (error %d)\n", ret);
return ret;
}
} while (status == 0xff);
if (status != 0) {
if (status != 0xff)
break;
}
if (status == 0xff) {
dev_err(line6->ifcdev, "write failed after %d retries\n",
count);
return -EIO;
} else if (status != 0) {
dev_err(line6->ifcdev, "write failed (error %d)\n", ret);
return -EINVAL;
}