On Thu, Oct 20, 2011 at 12:22:02PM +0200, Javier Martinez Canillas wrote: > On Thu, Oct 20, 2011 at 12:05 PM, Felipe Balbi <balbi@xxxxxx> wrote: > > 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. > > > > Yes, shouldn't ask here. I'm sorry. > > I just asked because I thought it could be a common problem for both > TI's kernel and upstream. But you are right I'll seek support with the > Arago people. > > Thanks a lot for your help and answers, no problem ;-) -- balbi
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