diff options
| -rw-r--r-- | common/usb_storage.c | 43 |
1 files changed, 22 insertions, 21 deletions
diff --git a/common/usb_storage.c b/common/usb_storage.c index 54f8e53c63..337c4e1fbd 100644 --- a/common/usb_storage.c +++ b/common/usb_storage.c @@ -938,31 +938,32 @@ do_retry: static void usb_stor_set_max_xfer_blk(struct usb_device *udev, struct us_data *us) { - unsigned short blk; - size_t __maybe_unused size; - int __maybe_unused ret; - -#if !CONFIG_IS_ENABLED(DM_USB) -#ifdef CONFIG_USB_EHCI_HCD /* - * The U-Boot EHCI driver can handle any transfer length as long as - * there is enough free heap space left, but the SCSI READ(10) and - * WRITE(10) commands are limited to 65535 blocks. + * Limit the total size of a transfer to 120 KB. + * + * Some devices are known to choke with anything larger. It seems like + * the problem stems from the fact that original IDE controllers had + * only an 8-bit register to hold the number of sectors in one transfer + * and even those couldn't handle a full 256 sectors. + * + * Because we want to make sure we interoperate with as many devices as + * possible, we will maintain a 240 sector transfer size limit for USB + * Mass Storage devices. + * + * Tests show that other operating have similar limits with Microsoft + * Windows 7 limiting transfers to 128 sectors for both USB2 and USB3 + * and Apple Mac OS X 10.11 limiting transfers to 256 sectors for USB2 + * and 2048 for USB3 devices. */ - blk = USHRT_MAX; -#else - blk = 20; -#endif -#else + unsigned short blk = 240; + +#if CONFIG_IS_ENABLED(DM_USB) + size_t size; + int ret; + ret = usb_get_max_xfer_size(udev, (size_t *)&size); - if (ret < 0) { - /* unimplemented, let's use default 20 */ - blk = 20; - } else { - if (size > USHRT_MAX * 512) - size = USHRT_MAX * 512; + if ((ret >= 0) && (size < blk * 512)) blk = size / 512; - } #endif us->max_xfer_blk = blk; |