> On Mon, Aug 04, 2008 at 06:48:22PM +0530, ext Gadiyar, Anand wrote:
> > MUSB RTL v1.4 has a hardware issue which results in a DMA controller
> > hang when TX and RX DMA channels are simultaneously enabled. This
> > affects at least OMAP2430 and OMAP34XX.
> >
> > Since RX transfers are in Mode 0 and anyway result in one DMA interrupt
> > per packet, we can use System DMA to unload the RX fifos. MUSB DMA can
> > be used for all TX channels as before.
> >
> > Tested with full-duplex TX and RX transfers using g_ether. Runs for 24
> > hours without a hang. Without this patch, the hang occurs within minutes.
> 
> I just don't like that amount of ifdefs, as we were discussing out of
> the list we should use runtime checks where possible.
> 
> Let's wait on this one since Anand will send another patch set later on
> this week.

Updated patch coming up. Run-time checks are still not implemented. It would
be nice to have, but I fail to see on what basis I can have the runtime check.
Suggestions are welcome.

I've left in only two #ifdefs - one for the dma callback function, and the other
for the call to omap_request_dma(). The other ifdefs are now gone - replaced 
with
runtime checks based on whether a system DMA channel has been acquired.

Also fixed a small bug which would make this patch not compile.

- Anand

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