From mboxrd@z Thu Jan 1 00:00:00 1970 From: Felipe Balbi Date: Wed, 20 Aug 2014 11:11:13 -0500 Subject: [U-Boot] [UBOOT RFC PATCH 07/13] usb: gadget: g_dnl: Explicitly set the max packet size in descriptor In-Reply-To: <20140820093413.21ab509d@amdc2363> References: <1408372115-4570-1-git-send-email-kishon@ti.com> <1408372115-4570-8-git-send-email-kishon@ti.com> <20140818143856.GF9662@saruman.home> <20140818165646.4487059c@amdc2363> <53F36F58.7060308@ti.com> <20140819154402.GL16085@saruman.home> <20140820093413.21ab509d@amdc2363> Message-ID: <20140820161113.GI24500@saruman.home> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Wed, Aug 20, 2014 at 09:34:13AM +0200, Lukasz Majewski wrote: > Hi Felipe, > > > On Tue, Aug 19, 2014 at 09:08:00PM +0530, Kishon Vijay Abraham I > > wrote: > > > > > > > > > On Monday 18 August 2014 08:26 PM, Lukasz Majewski wrote: > > > > Hi Kishon, > > > > > > > >>> Explicity set the max packet size in the device descriptor to > > > >>> 0x40 as specified in the device class specification for device > > > >>> firmware upgrade. Also changed debug to printf to explicitly > > > >>> notify the user if the device has been enumerated. > > > > > > > > It seems like this patch slipped without my attention ... > > > > > > > > Hence, I'd like to ask why you must hardcode the packet size here? > > > > > > http://www.usb.org/developers/devclass_docs/usbdfu10.pdf (in > > > section 4.2.1 DFU Mode Device Descriptor), specifies the > > > bMaxPacketSize0 can be 8,16,32,64. And the value we get from > > > gadget is 512. So hard coded it. > > > > as I mentioned, this should be changed on connection done interrupt. > > In the u-boot it is set up during binding the composite. look at dwc3. dwc3 has a connection done IRQ which also tells me the negotiated link speed. > > DFU has one of the poorest documentations for a USB Class and has some > > moronic definitions. > > Frankly speaking I prefer to have the worst standard than some > "brilliant" in house developed protocols. nobody is talking about changing the protocol. DFU was written back when Full speed was the fastest USB on earth. > > What happens if you want ot run DFU with a > > superspeed controller (such as dwc3) when connected to a superspeed > > port. We cannot use ep0 packet size as 64, right ? > > Correct me if I'm wrong, but MaxPacket for SS ep0 is 2^9 = 512B. > I'm curious if dfu-util will manage to handle ep0 MaxPacket size up to > 512B. > It not, then we shall be able to fallback to 64B. should be a test away. -- balbi -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: