On Wed, Jul 13, 2022 at 12:40:53PM +0100, John Keeping wrote: > On Tue, Jul 12, 2022 at 07:56:43PM -0700, Jack Pham wrote: > > Hi Wesley, > > > > On Tue, Jul 12, 2022 at 05:35:23PM -0700, Wesley Cheng wrote: > > > Since EP0 transactions need to be completed before the controller halt > > > sequence is finished, this may take some time depending on the host and the > > > enabled functions. Increase the controller halt timeout, so that we give > > > the controller sufficient time to handle EP0 transfers. > > > > > > Fixes: 861c010a2ee1 ("usb: dwc3: gadget: Refactor pullup()") > > > Suggested-by: Thinh Nguyen <Thinh.Nguyen@xxxxxxxxxxxx> > > > Signed-off-by: Wesley Cheng <quic_wcheng@xxxxxxxxxxx> > > > --- > > > Link: > > > https://lore.kernel.org/linux-usb/4988ed34-04a4-060a-ccef-f57790f76a2b@xxxxxxxxxxxx/ > > > > > > drivers/usb/dwc3/gadget.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c > > > index 41b7007358de..e32d7293c447 100644 > > > --- a/drivers/usb/dwc3/gadget.c > > > +++ b/drivers/usb/dwc3/gadget.c > > > @@ -2476,6 +2476,7 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend) > > > dwc3_gadget_dctl_write_safe(dwc, reg); > > > > > > do { > > > + msleep(1); > > > > Be aware that this probably won't sleep for *just* 1ms. From > > Documentation/timers/timers-howto.rst: > > > > msleep(1~20) may not do what the caller intends, and > > will often sleep longer (~20 ms actual sleep for any > > value given in the 1~20ms range). In many cases this > > is not the desired behavior. > > > > So with timeout==500 this loop could very well end up iterating for up > > to 10 seconds. Granted this shouldn't be called from any atomic context > > but just wanted to make sure that the effective increase in timeout as > > $SUBJECT intends is made clear here and that it's not overly generous. > > > > > reg = dwc3_readl(dwc->regs, DWC3_DSTS); > > > reg &= DWC3_DSTS_DEVCTRLHLT; > > > } while (--timeout && !(!is_on ^ !reg)); > > Does it make sense to convert this loop to use read_poll_timeout() and > make the timeout explicit, something like: > > ret = read_poll_timeout(dwc3_readl, reg, !(!is_on ^ !(reg & DWC3_DSTS_DEVCTRLHLT)), > 100, timeout * USEC_PER_MSEC, true, dwc->regs, DWC3_DSTS); > > ? Yeah I think it would make sense. Might even be worthwhile to revisit similar loops being performed in dwc3_send_gadget_generic_command() and dwc3_send_gadget_ep_cmd() which are currently spinning delay-lessly for a fixed number of iterations. Jack