Hello, Heiko Schocher wrote: > Hello, > > a while ago (see discussion here: > http://comments.gmane.org/gmane.linux.usb.general/54505), I found this > "USB timing Bug" on an am1808 based board: > > Heiko Schocher wrote: >> Hello Sergei, > [...] >> Sergei Shtylyov wrote: >>> Hello. >>> >>> On 11.11.2011 11:19, Felipe Balbi wrote: >>> >>>>> I try to bring up usb 2.0 support on an am1808 based >>>>> board and Linux version 3.1.0-rc10 and I am facing >>>>> some issues: > [...] >>>>> But if I add in drivers/usb/musb/da8xx.c >>>>> da8xx_musb_interrupt() a 10ms delay befor the >>>>> "if (status& (DA8XX_INTR_DRVVBUS<< DA8XX_INTR_USB_SHIFT)) {" >>>>> line usb works fine! >>>>> It also works without this timeout if I change the >>>>> "dev_dbg(musb->controller, "USB IRQ %08x\n", status);" >>>>> to >>>>> "printk(musb->controller, "USB IRQ %08x\n", status);" >>>>> >>>>> -> some timing issue, but I have no idea why! >>>>> (Maybe you have an idea?) >>>> unfortunately I don't know any details about DaVinci. >>> AM1808 is not exactly DaVinci, to be precise... >>> >>>> Sergei, are you able to help on this question ? >>> Maybe. :-) >> I hope it ;-) > > now I digged deeper and found this patch, which solves the > problem (without adding a 10 ms delay): > > ----------------------------- > diff --git a/drivers/usb/musb/da8xx.c b/drivers/usb/musb/da8xx.c > index d32aa4d..6a6b17b 100644 > --- a/drivers/usb/musb/da8xx.c > +++ b/drivers/usb/musb/da8xx.c > @@ -297,6 +297,7 @@ static irqreturn_t da8xx_musb_interrupt(int irq, void *hci) > unsigned long flags; > irqreturn_t ret = IRQ_NONE; > u32 status; > + int flag = 1; > > spin_lock_irqsave(&musb->lock, flags); > > @@ -368,6 +363,7 @@ static irqreturn_t da8xx_musb_interrupt(int irq, void *hci) > musb->xceiv->default_a = 0; > musb->xceiv->state = OTG_STATE_B_IDLE; > portstate(musb->port1_status &= ~USB_PORT_STAT_POWER); > + flag = 0; > } > > dev_dbg(musb->controller, "VBUS %s (%s)%s, devctl %02x\n", > @@ -378,7 +374,7 @@ static irqreturn_t da8xx_musb_interrupt(int irq, void *hci) > ret = IRQ_HANDLED; > } > > - if (musb->int_tx || musb->int_rx || musb->int_usb) > + if (flag && ((musb->int_tx || musb->int_rx || musb->int_usb))) > ret |= musb_interrupt(musb); > > eoi: > ----------------------------- > > If we get an DA8XX_INTR_DRVVBUS IRQ, in the else case > > musb->xceiv->state = OTG_STATE_B_IDLE; > > is set, but overwritten in the musb_interrupt() call, which results > in not starting the "Poll for ID change" timer ... as I am not an USB > expert, posting this intermediate result here, maybe someone have an > idea/explanation if this patch is the way to go, or what would be a > better solution? ping? Some comments/ideas? bye, Heiko -- DENX Software Engineering GmbH, MD: Wolfgang Denk & Detlev Zundel HRB 165235 Munich, Office: Kirchenstr.5, D-82194 Groebenzell, Germany Phone: (+49)-8142-66989-10 Fax: (+49)-8142-66989-80 Email: wd@xxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
