Hi, On Thu, Oct 20, 2011 at 11:52:27AM +0200, Javier Martinez Canillas wrote: > > On Thu, Oct 20, 2011 at 10:19:41AM +0200, Javier Martinez Canillas wrote: > >> Sorry if this is not the right place to ask this. But I didn't find an > >> USB user mailing list. > >> > >> We have a custom TI DM3730 board using a Mentor Graphics's USB > >> controller (musb_hdrc). We are using the usb ethernet gadget (g_ether) > >> to create a point-to-point ethernet network between the board and a > >> host PC. > >> > >> The problem is that even when the bus is USB 2.0 with a theoretical > >> transfer rate of 480 Mbps, we are only getting about 55 Mbps from the > >> host to the target and about 65 Mbps from the target to the host. > >> > >> We are pretty sure that the board can handle more traffic than that > >> since with a fast Ethernet 100BASE-TX connection we get about 93 Mbps. > >> > >> Is correct to get so low traffic with the usb ethernet gadget? > > > > with MUSB, yes :-s > > > > Sorry. The problem is that it has so many silicon issues that the very > > powerful mode1 DMA can't be used in all situations. Also, in case of > > ethernet packets, we will get unaligned buffers, which MUSB's internal > > DMA engine can't handle, then that packet has to be transferred via PIO. > > > > I don't think there's anything which could be done in this case :-( > > I forgot to tell you more about our environment. We are using an Arago > project v2.6.37 kernel for OMAP3 devices. Then, I'm sorry, but you need to seek support with Arago, or your TI representative, for that matter. Community can't help. -- balbi
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