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Commit 0dd1aab7 authored by Mike Lockwood's avatar Mike Lockwood
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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
parent d5039305

libusbhost/usbhost.c

+5 −2
Original line number Diff line number Diff line
@@ -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 @@ const struct usb_device_descriptor* usb_device_get_device_descriptor(struct usb_ 
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;