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>
diff --git a/sound/usb/line6/driver.c b/sound/usb/line6/driver.c
index 2f9b74e..f2ee804 100644
--- a/sound/usb/line6/driver.c
+++ b/sound/usb/line6/driver.c
@@ -297,6 +297,7 @@
}
#define LINE6_READ_WRITE_STATUS_DELAY 2 /* milliseconds */
+#define LINE6_READ_WRITE_MAX_RETRIES 50
/*
Read data from device.
@@ -307,6 +308,7 @@
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 @@
}
/* 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 @@
"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 @@
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 @@
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 @@
"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;
}