Wait for device to disappear after reboot-bootloader.
(Linux only for now) With fastboot reading serial numbers from sysfs, it had
become possible for a fastboot command issued immediately after rebooting
the bootloader to fail, because sysfs still thought the device was online.
To prevent this, after reboot-bootloader we wait for the device to disconnect.
Also made usb_read and usb_write fail immediately if the descriptor has been
closed; this prevents an incorrect error message ("Bad file descriptor")
when errors from fb_getvar are ignored (e.g., by fb_format_supported).
Also removed unused fd param from filter_usb_device, and simplified logic
in usb_write by using do/while instead of a special case for len == 0.
Change-Id: I799b857eab411fd8ad25f5777fc61c685152ea86
diff --git a/fastboot/usb_linux.c b/fastboot/usb_linux.c
index 9153c8d..f2ce226 100644
--- a/fastboot/usb_linux.c
+++ b/fastboot/usb_linux.c
@@ -50,10 +50,17 @@
#endif
#include <asm/byteorder.h>
+#include "fastboot.h"
#include "usb.h"
#define MAX_RETRIES 5
+/* Timeout in seconds for usb_wait_for_disconnect.
+ * It doesn't usually take long for a device to disconnect (almost always
+ * under 2 seconds) but we'll time out after 3 seconds just in case.
+ */
+#define WAIT_FOR_DISCONNECT_TIMEOUT 3
+
#ifdef TRACE_USB
#define DBG1(x...) fprintf(stderr, x)
#define DBG(x...) fprintf(stderr, x)
@@ -103,7 +110,7 @@
return 0;
}
-static int filter_usb_device(int fd, char* sysfs_name,
+static int filter_usb_device(char* sysfs_name,
char *ptr, int len, int writable,
ifc_match_func callback,
int *ept_in_id, int *ept_out_id, int *ifc_id)
@@ -308,7 +315,7 @@
n = read(fd, desc, sizeof(desc));
- if(filter_usb_device(fd, de->d_name, desc, n, writable, callback,
+ if(filter_usb_device(de->d_name, desc, n, writable, callback,
&in, &out, &ifc) == 0) {
usb = calloc(1, sizeof(usb_handle));
strcpy(usb->fname, devname);
@@ -340,26 +347,11 @@
struct usbdevfs_bulktransfer bulk;
int n;
- if(h->ep_out == 0) {
+ if(h->ep_out == 0 || h->desc == -1) {
return -1;
}
- if(len == 0) {
- bulk.ep = h->ep_out;
- bulk.len = 0;
- bulk.data = data;
- bulk.timeout = 0;
-
- n = ioctl(h->desc, USBDEVFS_BULK, &bulk);
- if(n != 0) {
- fprintf(stderr,"ERROR: n = %d, errno = %d (%s)\n",
- n, errno, strerror(errno));
- return -1;
- }
- return 0;
- }
-
- while(len > 0) {
+ do {
int xfer;
xfer = (len > MAX_USBFS_BULK_SIZE) ? MAX_USBFS_BULK_SIZE : len;
@@ -378,7 +370,7 @@
count += xfer;
len -= xfer;
data += xfer;
- }
+ } while(len > 0);
return count;
}
@@ -390,7 +382,7 @@
struct usbdevfs_bulktransfer bulk;
int n, retry;
- if(h->ep_in == 0) {
+ if(h->ep_in == 0 || h->desc == -1) {
return -1;
}
@@ -458,3 +450,18 @@
{
return find_usb_device("/sys/bus/usb/devices", callback);
}
+
+/* Wait for the system to notice the device is gone, so that a subsequent
+ * fastboot command won't try to access the device before it's rebooted.
+ * Returns 0 for success, -1 for timeout.
+ */
+int usb_wait_for_disconnect(usb_handle *usb)
+{
+ double deadline = now() + WAIT_FOR_DISCONNECT_TIMEOUT;
+ while (now() < deadline) {
+ if (access(usb->fname, F_OK))
+ return 0;
+ usleep(50000);
+ }
+ return -1;
+}