| Message ID | 11BBAEC7-0B26-40FE-963E-811F7853F2FE@tecnorama.it (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
* Moreno Bartalucci <moreno.bartalucci@tecnorama.it> [170327 23:12]: > > Il giorno 27 mar 2017, alle ore 19:15, Bin Liu <b-liu@ti.com> ha scritto: > > > > […] > > > > The MUSB otg state machine has been changed in many place since the last > > time I looked at it, and I am not sure how exactly it works now. > > > > If the $subject patch can correctly keep the VBUS on for host-only mode, > > we can somehow use dr_modei value to distinguish the mode. We don't have > > to create a new vbus-always-on-in-host-mode flag. VBUS has to be always > > on in host-only mode anyway, until some error condition happens. > > > > During my research, I used this patch to try to print the status of the usb port: > > --- a/drivers/usb/musb/musb_dsps.c 2017-03-13 09:34:31.000000000 +0100 > +++ b/drivers/usb/musb/musb_dsps.c 2017-03-13 09:36:02.000000000 +0100 > @@ -245,6 +245,8 @@ static void otg_timer(unsigned long _mus > dev_dbg(musb->controller, "Poll devctl %02x (%s)\n", devctl, > usb_otg_state_string(musb->xceiv->otg->state)); > > + dev_emerg(musb->controller, "musb->xceiv->otg->state=%s, musb->port_mode=%d\n", usb_otg_state_string(musb->xceiv->otg->state),(int)musb->port_mode); > + > spin_lock_irqsave(&musb->lock, flags); > switch (musb->xceiv->otg->state) { > case OTG_STATE_A_WAIT_BCON: > > Unless I did something wrong, maybe it’s worth to notice that before the patch that apparently introduced this bug (2f3fd2c5bde1f94513c3dc311ae64494085ec371) I got nothing printed anywhere. > With that patch applied, instead, I got the line printed in dmesg. > I might be wrong but my assumption is that without that patch otg_timer was never called. > If this is true, it would explain why writing 0 on DEVCTL didn’t bother anything: it never happened. OK yeah that makes sense. Thanks, Tony -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
--- a/drivers/usb/musb/musb_dsps.c 2017-03-13 09:34:31.000000000 +0100 +++ b/drivers/usb/musb/musb_dsps.c 2017-03-13 09:36:02.000000000 +0100 @@ -245,6 +245,8 @@ static void otg_timer(unsigned long _mus dev_dbg(musb->controller, "Poll devctl %02x (%s)\n", devctl, usb_otg_state_string(musb->xceiv->otg->state)); + dev_emerg(musb->controller, "musb->xceiv->otg->state=%s, musb->port_mode=%d\n", usb_otg_state_string(musb->xceiv->otg->state),(int)musb->port_mode); + spin_lock_irqsave(&musb->lock, flags); switch (musb->xceiv->otg->state) { case OTG_STATE_A_WAIT_BCON: