Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932907AbbFIPQ7 (ORCPT ); Tue, 9 Jun 2015 11:16:59 -0400 Received: from iolanthe.rowland.org ([192.131.102.54]:38482 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1753837AbbFIPQt (ORCPT ); Tue, 9 Jun 2015 11:16:49 -0400 Date: Tue, 9 Jun 2015 11:16:48 -0400 (EDT) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Kishon Vijay Abraham I cc: Michael Trimarchi , Felipe Balbi , , , , , Subject: Re: [RFC PATCH] usb: dwc3: ep0: Fix mem corruption on OUT transfers of more than 512 bytes In-Reply-To: <55770173.7060801@ti.com> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1128 Lines: 29 On Tue, 9 Jun 2015, Kishon Vijay Abraham I wrote: > > Why not just make the bounce buffer size the same as the maxpacket > > size? In other words, 1024 bytes instead of 512, for ep0 on a USB-3 > > device. > > It would still be possible for the host to send data more than 1024 bytes no? Yes. > When working with DFU gadget, I've seen host sends data upto 4KB. Changing the > bounce buffer size might not be able to fix all the cases IMO. The actual fix > will be something like [1] > > [1] -> http://comments.gmane.org/gmane.linux.kernel/1883688 But with a bounce buffer that's only 512 bytes long, you can never send an entire packet's worth of data. If the bounce buffer is 1024 bytes then you can send the entire first packet. When that's done, you can send the second packet. And so on. It wouldn't be quite as fast, but for ep0 that shouldn't matter. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/