Recently Ramya tried to enqueue a very large transfer to the xHCI driver and filled the endpoint ring for that bulk endpoint. Because of that I've been looking at doing dynamic ring resizing. I've run into a slight problem. In xhci-pci.c, David Vrabel set hcd->self.sg_tablesize to (TRBS_PER_SEGMENT - 1), or 63 entries. The USB storage driver currently sets the Scsi_Host->sg_tablesize based on the hcd's table size, which limits the number of scatter-gather entries. So even if I add more segments to the rings, the driver will never enqueue a transfer with more than 63 sglist entries. If I want to dynamically expand the rings to include multiple segments and thus support more sglist entries, what should I set hcd->self.sg_tablesize to? If I set it to something large (like EHCI sets it to ~0), can I reject transfers if I run out of memory while allocating new ring segments? Should I use -E2BIG or -ENOMEM? Sarah Sharp -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
