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? 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
