USB devio splits large transaction into 16 KiB buffers in scatter-gather
lists. Unfortunately, this mechanism seems unreliable most certainly because
of issue #4809 "DDE Linux struct page object aliasing".

--- src/linux/drivers/usb/core/devio.c
+++ src/linux/drivers/usb/core/devio.c
@@ -53,7 +53,7 @@
 
 #define USB_MAXBUS			64
 #define USB_DEVICE_MAX			(USB_MAXBUS * 128)
-#define USB_SG_SIZE			16384 /* split-size for large txs */
+#define USB_SG_SIZE			(1024 * 1024) /* split-size for large txs */
 
 /* Mutual exclusion for ps->list in resume vs. release and remove */
 static DEFINE_MUTEX(usbfs_mutex);