libusbhost: Fix problem reading USB string descriptors on some quirky devices
Some devices fail to send USB string descriptors if you attempt to read more
than 255 bytes
Bug: 21871761
Change-Id: Id5b8865179f80523f0ad5b6028d49dd99db2b36b
diff --git a/libusbhost/usbhost.c b/libusbhost/usbhost.c
index 40b8b9f..b8e3215 100644
--- a/libusbhost/usbhost.c
+++ b/libusbhost/usbhost.c
@@ -56,6 +56,9 @@
#define USB_FS_ID_SCANNER USB_FS_DIR "/%d/%d"
#define USB_FS_ID_FORMAT USB_FS_DIR "/%03d/%03d"
+// Some devices fail to send string descriptors if we attempt reading > 255 bytes
+#define MAX_STRING_DESCRIPTOR_LENGTH 255
+
// From drivers/usb/core/devio.c
// I don't know why this isn't in a kernel header
#define MAX_USBFS_BUFFER_SIZE 16384
@@ -449,8 +452,8 @@
char* usb_device_get_string(struct usb_device *device, int id)
{
char string[256];
- __u16 buffer[128];
- __u16 languages[128];
+ __u16 buffer[MAX_STRING_DESCRIPTOR_LENGTH / sizeof(__u16)];
+ __u16 languages[MAX_STRING_DESCRIPTOR_LENGTH / sizeof(__u16)];
int i, result;
int languageCount = 0;