From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bin Liu Subject: Re: [PATCHv2] dmaengine: cppi41: Fix oops in cppi41_runtime_resume Date: Tue, 17 Jan 2017 13:46:14 -0600 Message-ID: <20170117194614.GB17480@uda0271908> References: <20170113215936.GF2630@atomide.com> <20170116233329.GF7403@atomide.com> <20170116235428.GG7403@atomide.com> <20170117125919.GA31716@uda0271908> <20170117161138.GJ7403@atomide.com> <20170117162152.GE31716@uda0271908> <20170117163103.GO7403@atomide.com> <20170117164846.GG31716@uda0271908> <20170117173922.GR7403@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Content-Disposition: inline In-Reply-To: <20170117173922.GR7403-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Tony Lindgren Cc: Grygorii Strashko , Dan Williams , Vinod Koul , Daniel Mack , Felipe Balbi , Johan Hovold , Peter Ujfalusi , Sekhar Nori , Sebastian Andrzej Siewior , dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Andy Shevchenko , Kevin Hilman , Patrick Titiano , Sergei Shtylyov List-Id: linux-omap@vger.kernel.org On Tue, Jan 17, 2017 at 09:39:23AM -0800, Tony Lindgren wrote: > * Bin Liu [170117 08:49]: > > On Tue, Jan 17, 2017 at 08:31:03AM -0800, Tony Lindgren wrote: > > > * Bin Liu [170117 08:22]: > > > > On Tue, Jan 17, 2017 at 08:11:39AM -0800, Tony Lindgren wrote: > > > > > * Bin Liu [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. -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html