On Tue, Jan 17, 2017 at 09:39:23AM -0800, Tony Lindgren wrote:
> * Bin Liu <[email protected]> [170117 08:49]:
> > On Tue, Jan 17, 2017 at 08:31:03AM -0800, Tony Lindgren wrote:
> > > * Bin Liu <[email protected]> [170117 08:22]:
> > > > On Tue, Jan 17, 2017 at 08:11:39AM -0800, Tony Lindgren wrote:
> > > > > * Bin Liu <[email protected]> [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.
Sure, I will spend some time on this tomorrow morning, and let you know.
>
> 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;
I think you also need to add more cleanup in here when not use dma,
as in musb_ep_program():
746 if (is_out && !len) {
747 use_dma = 0;
748 csr = musb_readw(epio, MUSB_TXCSR);
749 csr &= ~MUSB_TXCSR_DMAENAB;
750 musb_writew(epio, MUSB_TXCSR, csr);
751 hw_ep->tx_channel = NULL;
752 }
Regards,
-Bin.
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