* Bin Liu <b-liu@xxxxxx> [170117 08:49]:
> On Tue, Jan 17, 2017 at 08:31:03AM -0800, Tony Lindgren wrote:
> > * Bin Liu <b-liu@xxxxxx> [170117 08:22]:
> > > On Tue, Jan 17, 2017 at 08:11:39AM -0800, Tony Lindgren wrote:
> > > > * Bin Liu <b-liu@xxxxxx> [170117 05:00]:
> > > > > On Mon, Jan 16, 2017 at 03:54:29PM -0800, Tony Lindgren wrote:
> > > > > > Anyways, for the -rc series oops, we can just leave out the WARN_ON
> > > > > > parts for now until drivers/usb/musb/musb_cppi41.c is fixed too.
> > > > >
> > > > > Giving that cppi is a submodule inside the usb subsysytem and it does't
> > > > > have separate power rail or clock, what is the benefit to adding runtime
> > > > > PM in the cppi driver?
> > > >
> > > > Good question. We need at least minimal support to enable things for
> > > > probe and then idle cppi41 properly if only cppi41.ko is loaded with no
> > > > USB modules.
> > > >
> > > > But yeah now that musb does runtime PM based on the cable detection, we
> > > > pretty much guarantee that cppi41 is always enabled when USB is in use.
> > > >
> > > > And if there are no other devices using cppi41 dma on davinci, we can
> > > > simplify the PM runtime a bit for cppi41.
> > >
> > > This might be a good idea. I didn't have much time to play with this
> > > cppi41 runtime PM, but it seems I am having more issues than you and
> > > others seeing.
> >
> > What kind of additional issues are you seeing not described in the $subject
> > patch?
>
> I didn't take a note and don't remember if those are in the $subject
> patch. But
>
> - enumeration begining with a reset that the device doesn't accept
> address X, error code -71; or
Some of this could be fixed by $subject patch if caused by a race.
Some of it I'm suspecting might be a different issue where cppi41 dma
will just hang until the device is disconnected on 1 sized in dma transfer.
See the experimental patch below.
> - console fooding with cppi error code -115 after thumb drive enumeration.
This should get fixed with the $subject patch if we additionally set
the autosuspend_delay to something sufficient, like 1000.
> Again, I only tried for a few minutes and didn't take a note, since I
> don't have time to look at this ATM.
Well I'll post what I think we should fix for the -rc series for cppi41.
If you can then please test that a bit and see if it works. Assuming
things work, then all the other changes can be done later on with no
rush.
Regards,
Tony
8< ----------------------------------------
diff --git a/drivers/usb/musb/musb_host.c b/drivers/usb/musb/musb_host.c
--- a/drivers/usb/musb/musb_host.c
+++ b/drivers/usb/musb/musb_host.c
@@ -751,6 +751,15 @@ static void musb_ep_program(struct musb *musb, u8 epnum,
hw_ep->tx_channel = NULL;
}
+ /*
+ * At least cppi41 in dma will just hang with size of 1 until the
+ * device is connected. For sizes less than 8 it seems to take a
+ * long time to complete. Let's use minimum size of 16 to avoid
+ * tiny in DMA transfers.
+ */
+ if (!is_out && (len < 16))
+ use_dma = 0;
+
/* candidate for DMA? */
dma_controller = musb->dma_controller;
if (use_dma && is_dma_capable() && epnum && dma_controller) {
--
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